WorksheetsFall Semester Final
Total questions: 180
Worksheet time: 45hrs 0mins
Which living structure is an exception to the cell theory?
Striated muscle fibres
A single-celled alga carrying out all of the functions of life
The artificial synthesis of the organic molecule urea
A multicellular organism with cells undertaking specialized roles
What function is performed by the part of the cell shown in the electron micrograph?
Locomotion
Synthesis of proteins
Movement of chromosomes
Breakdown of cellular organelles
Which sequence has the cells arranged according to their ability to differentiate, starting from the least able?
bone marrow, neuron, embryonic, umbilical
neuron, bone marrow, umbilical, embryonic
umbilical, embryonic, bone marrow, neuron
embryonic, umbilical, bone marrow, neuron
The electron micrograph shows a thin section through a plant mesophyll cell. What is the magnification of the image?
× 75
× 300
× 3000
× 7500
If cells of a multicellular organism have the same genes, how can there be many different cell types in a body?
Some genes but not others are expressed in each cell type.
Cells lose some genes as development occurs.
Genes do not determine the structure of a cell.
Cells must practice division of labour in order to survive.
What feature of both striated muscle and aseptate fungal hyphae is different from typical cell structure?
They have multiple nuclei within a structural unit.
They have a cell wall that is not made of cellulose.
They have plasmids.
They have an absence of cholesterol in the plasma membrane.
Which organelle provides evidence that eukaryotic cells originated when large prokaryotes engulfed small free-living prokaryotes?
Chloroplast
Nucleoid
80S ribosome
Vacuole
When compared to other body cells, which characteristic of stem cells is the most important for therapeutic uses?
Less differentiation
Less excretion
Lower rate of reproduction
Lower rate of metabolism
The giant alga Acetabularia has a feature that suggests it is an exception to the cell theory. What feature is this?
It lacks a nucleus.
It lacks a cell wall.
It has only one mitochondrion.
It lacks subdivision into separate cells.
Which feature of striated muscle cells allows them to be considered as a possible exception to the cell theory?
They are found in multicellular organisms.
They contain more than one nucleus.
They are specialized for movement.
They do not carry out mitosis.
Which characteristic of stem cells makes them useful for treating Stargardt’s disease?
They can differentiate into retinal cells.
They are readily available from especially created embryos.
They transport white blood cells to the eyes.
They divide by binary fission so provide sufficient cells.
What provides evidence for the endosymbiotic theory?
Mitochondrial DNA in eukaryotic cells
70S ribosomes in prokaryotic cells
Gene transfer from prokaryotic cells to eukaryotic cells using plasmids
Prokaryotic cells (Escherichia coli) in the large intestine digest proteins
In mammals, mature red blood cells are specialized in that they lack nuclei, mitochondria or ribosomes. Which statement applies to red blood cells?
No chemical reactions take place within their cytoplasm.
They cannot produce new enzymes.
Materials cannot enter red blood cells.
Materials cannot exit red blood cells.
What do chloroplasts and mitochondria have in common?
Both are found in the cells of Filicinophyta.
Both contain grana.
Both occur in all eukaryotic cells.
Both are found in a Paramecium.
The electron micrograph shows a section through a cell. What is the name of the cell component labeled Y? Remember to zoom in on the image!
Golgi apparatus
Nucleus
Cytoplasm
Vacuole
The image shows an electron micrograph of part of a cell. Which features do the two structures labelled X and Y have in common?
They are surrounded by a double membrane.
They contain 70S ribosomes.
They contain naked DNA.
They are only found in leaf cells.
Which structures are found only in prokaryotic cells?
Ribosomes
Pili
Cell walls
Flagella
What evidence from the image of Paramecium indicates whether the organism is a prokaryote or a eukaryote?
Compartments in the cell indicate that it is a eukaryote.
No nucleus indicates that the cell is a prokaryote.
Lack of a cell wall indicates that the cell is a eukaryote.
It is a unicellular organism, so it must be a prokaryote.
Which structure found in eukaryotes has a single membrane?
Nucleus
Lysosome
Chloroplast
Mitochondrion
Which organelle is involved in generating vesicles destined for the cell membrane?
Golgi apparatus
Smooth endoplasmic reticulum
Rough endoplasmic reticulum
Lysosome
The image shows part of a mammalian cell. What is the specialized function of this mammalian cell? REMEMBER, you can enlarge the picture by clicking on it.
Locomotion
Absorption
Reception of stimuli
Gas exchange
Which features of phospholipids give them their amphipathic properties?
Basic phosphate groups and acidic lipids
Acidic phosphate groups and basic lipids
Hydrophobic phosphate groups and hydrophilic fatty acids
Hydrophilic phosphate groups and hydrophobic fatty acids
The Davson–Danielli model of membrane structure proposed that membranes were composed of a phospholipid bilayer that lies between two layers of globular proteins, as shown in this diagram. What evidence supported this model?
An electron micrograph that showed two dark lines with a lighter band in between
Freeze-fracture electron microscopy
Evidence that all membranes are identical
The hydrophobic regions of protein would be in contact with water
Which statement applies to cholesterol?
It is hydrophobic and found on the outside of the phospholipid bilayer.
It is hydrophilic and found inside the phospholipid bilayer.
It impacts membrane fluidity.
It is transported in association with glucose in the blood.
What special property of phospholipid molecules explains their ability to spontaneously assemble into a lipid bilayer?
They are hydrophobic.
They are amphipathic.
They are saturated.
They are hydrophilic
Which is an essential feature of the Davson–Danielli model of membrane structure?
A phospholipid monolayer with intrinsic and extrinsic proteins
A layer of protein sandwiched between two layers of lipid
A phospholipid bilayer with intrinsic and extrinsic proteins
A layer of lipid sandwiched between two layers of protein
What part of the plasma membrane is fluid, allowing the movement of proteins in accordance with the fluid mosaic model? Make sure to click on the picture.
A
B
C
D
Which molecule regulates the fluidity of cell membranes?
Phospholipid
Cholesterol
Glycoprotein
Peripheral protein
In the diagram, which structure is an intrinsic or integral protein?
A
B
C
D
What is a role of cholesterol in animal cells?
It increases body fat.
It controls membrane fluidity.
It lines the inner wall of capillaries.
It is a constituent of bile.
Which evidence falsifies the Davson–Danielli model?
I. The presence of globular proteins within the phospholipid bilayer
II. Non-polar amino acids cause proteins to remain embedded in membranes
III. Membrane proteins remain in a fixed position inside a membrane
I only
I and II only
II and III only
I, II and III
The cell membrane model proposed by Davson–Danielli was a phospholipid bilayer sandwiched between two layers of globular protein. Which evidence led to the acceptance of the Singer–Nicolson model?
The orientation of the hydrophilic phospholipid heads towards the proteins
The formation of a hydrophobic region on the surface of the membrane
The placement of integral and peripheral proteins in the membrane
The interactions due to amphipathic properties of phospholipids
How is facilitated diffusion in axons similar to active transport?
They both require the energy of ATP.
They both move substances against a concentration gradient.
They both use sodium–potassium pumps.
They are both carried out by proteins embedded in the axon membrane.
A human organ is being prepared for transplant. In what type of solution must it be bathed?
A hypertonic solution
A hypotonic solution
Pure water containing no solutes
A solution with the same osmolarity as the organ tissue
Which graph best represents the relationship between the concentration of chloride ions in the external environment of a cell and the rate at which the chloride ions move by facilitated diffusion into the cytoplasm of the cell?
A
B
C
D
The diagram shows a section through a membrane. What are the modes of transport in the diagram?
I: Simple Diffusion, II: Osmosis
I: Active Transport, II: Facilitated Diffusion
I: Simple Diffusion, II: Facilitated Diffusion
I: Facilitated Diffusion, II: Active Transport
By which process do potassium ions move through potassium channels in axons?
Active transport
Exocytosis
Facilitated diffusion
Simple diffusion
Which process(es) occur(s) by osmosis?
I. Uptake of water by cells in the wall of the intestine
II. Loss of water from a plant cell in a hypertonic environment
III. Evaporation of water from sweat on the skin surface
I only
I and II only
II and III only
I, II and III
The table shows concentrations of potassium ions and sodium ions inside and outside human cells. What explains these concentrations?
Potassium ions diffuse in and sodium ions diffuse out.
Sodium ions diffuse in and potassium ions diffuse out.
Active transport pumps sodium ions in and potassium ions out.
Active transport pumps sodium ions out and potassium ions in.
Neural pathways in living brains can now be mapped by tracking the movement of water molecules inside axons. What keeps water molecules inside axons?
Plasma membrane
Hydrogen bonding
Pump proteins
Synapse
How does potassium move across the membrane of a neuron during repolarization?
Simple diffusion
Facilitated diffusion
Endocytosis
Active transport
The salt concentration inside an animal cell is 1.8 %. The salt concentration in the surrounding medium becomes 5 %. What will be the likely response?
The cell will gain water from the medium.
The cell will lose salt to the medium.
The cell will remain unchanged.
The cell will shrink from loss of water.
A dialysis membrane was set up to model digestion and absorption in the small intestine. What is a limitation of this model?
There can be no active transport.
Maltose will pass through the membrane.
Lipase should be present with protein.
The membrane is not permeable to starch.
How do both mitochondria and chloroplasts provide evidence for the endosymbiotic theory?
They have double membranes.
They have 80S ribosomes similar to prokaryotes.
They contain the same DNA as the nucleus of the cell.
They exist together in eukaryote cells for their mutual benefit.
Which statement is evidence for the endosymbiotic theory?
Chloroplasts contain 70S ribosomes.
Protein synthesis occurs in the cytoplasm.
Organic molecules can be synthesised abiotically.
RNA is self-replicating.
The electron micrograph shows a section through a cell. Which feature of the cell in the micrograph is consistent with the endosymbiotic theory?
X has a single membrane.
Y has a double membrane.
X contains 70S ribosomes.
Y contains 80S ribosomes.
Which statement provides evidence for endosymbiosis?
Early prokaryotes contributed to a large increase in oxygen in the atmosphere.
Eukaryotic mitochondria and chloroplasts have their own circular DNA.
Certain groups of ancient prokaryotes developed mechanisms to carry out aerobic respiration.
Experiments by Miller and Urey produced simple organic molecules in abiotic conditions.
Apparatus was set up as shown to collect data. The graph shows the results after 47 minutes of data collection. What causes the rates to differ?
I. Different concentration gradients at the start
II. Diffusion of sugar is initially greater in Y than in X
III. The systems are reaching equilibrium over time
I only
II only
I and III only
II and III only
Pasteur carried out a series of experiments that provided strong evidence against a widely supported theory. What was this theory?
Endosymbiosis
Spontaneous generation
Conservative replication of DNA
Evolution
What is evidence for the endosymbiotic theory?
RNA can catalyze metabolic reactions.
Meteorites contain organic molecules.
Amino acids can be synthesized from inorganic compounds.
Mitochondria possess their own DNA.
The statement relates to Pasteur’s experiments. What did this statement suggest?
Mold evolved by endosymbiosis.
Oxygen is required for anaerobic respiration.
Cells can only be formed by division of pre-existing cells.
Nutrients are a requirement for mold growth.
The graph shows the mitotic index in the roots of lentil plants at different distances from the end of the root. What can be deduced from the graph?
As the distance from the end of the root increases, more cells are undergoing mitosis.
At 0.5 mm from the end of the root, most of the cells are in prophase.
There were fewer cells observed at 1.5 mm than at 0.5 mm.
As the distance from the end of the root increases, the percentage of cells in interphase increases.
A tissue sample was examined under the microscope in order to determine a mitotic index. The number of cells in each stage of the cell cycle was determined and the data were entered into a table. What is the mitotic index?
0.125
0.25
0.75
1.00
How many chromosomes are there in a cell during anaphase of mitosis, if the diploid number of the cell is 20?
10
20
40
80
In the micrograph, which letter points to a cell in anaphase?
A
B
C
D
Students examined micrographs and counted cells in the different stages of mitosis as well as those cells with no visible chromosomes. The table shows their results. What is the mitotic index?
0.2
0.4
0.6
0.7
The table shows the number of cells in various stages of the cell cycle in four samples of ovarian tissue from different patients. Which tissue sample A, B, C or D has the highest mitotic index?
A
B
C
D
What explains the appearance of the cell in the micrograph?
The cell is dying.
The DNA is replicating.
The cell is in metaphase.
The cell is in telophase.
Which processes are involved in the development of cancer?
I. Mutations occur in oncogenes.
II. Oncogenes prevent cancer.
III. Oncogenes affect cell cycle regulatory proteins.
I and II only
I and III only
II and III only
I, II and III
The diagram represents the nucleus of a cell 2 n = 8 in late prophase of mitosis. Which diagram represents a cell from the same species in anaphase II of meiosis?
How does mitosis produce two genetically identical nuclei?
By separation of homologous chromosomes
By separation of sister chromatids
By division of the cytoplasm into two equal cells
By division of the nuclear membrane into two equal parts
The concentrations of cyclins rise and fall in cells at certain times. What times are these?
Day and night
Seasons of the year
Stages of mitosis and interphase
Developmental stages in the life cycle
The image shows cells in the different stages of mitosis. Which cell is in telophase?
A
B
C
D
What occurs during meiosis but not mitosis?
Spindles are formed from microtubules.
Chromosome number is conserved.
Homologous chromosomes pair up.
Centromeres split.
Which diagram(s) represent(s) processes used in asexual reproduction?
I only
I and II only
II only
I, II and III
When during the cell cycle does DNA replication take place?
A
B
C
D
The graph shows the survival probabilities for current smokers and for those who never smoked among women 30 to 80 years of age. What can be deduced from this graph?
There is a correlation between smoking and cancer.
Smoking reduces life expectancy.
Smoking causes cancer.
70 % of smokers survive to 80 years old.
Which mitotic phase is labeled X in the micrograph of an onion (Allium cepa) root tip?
Prophase
Metaphase
Anaphase
Telophase
Testosterone is a hormone that is important for male reproductive development. To which group of compounds does testosterone belong? HINT: Chemical Formula is C19H28O2
Nucleotides
Carbohydrates
Lipids
Amino acids
Which process is an example of catabolism?
Translation of mRNA
Replication of DNA
Hydrolysis of protein
Synthesis of a disaccharide
What are the type of reaction and the product(s) shown in this reaction?
Reaction: Condensation, Products: two nucleotides
Reaction: Condensation, Products: one dinucleotide
Reaction: hydrolysis, Products: two nucleotides
Reaction: hydrolysis, Products: one dinucleotide
In which processes are macromolecules broken down into monomers?
Anabolism and catabolism
Catabolism and hydrolysis
Hydrolysis and reduction
Reduction and anabolism
Which type of chemical reaction is an example of anabolism?
Photolysis
Combustion
Hydrolysis
Condensation
What feature of carbon makes it most suitable as a basis for life?
Its abundance in nature
Its bonding properties
Its reactivity to light
Its presence in the early atmosphere of the Earth
Which reaction is an example of catabolism?
Photolysis of water
Denaturation of a protein by a change in pH
Production of maltose from amylose by amylase
Condensation of glucose to form starch
Which of the following molecules is an amino acid?
The diagram shows a cycle of reactions that occurs in human liver cells. Which term describes the overall reactions of this cycle?
Oxidation
Catabolism
Condensation
Metabolism
What is the benefit to living organisms that water has a high specific heat capacity?
Heat can be lost from the skin when sweat evaporates.
Aquatic environments do not have a great fluctuation in their temperature.
The amount of heat stored by water is highly predictable.
It allows water to be a solvent for chemical reactions at body temperature.
What is the term for the attraction of water molecules to other water molecules?
Surface tension
Capillary action
Cohesion
Adhesion
What is a property of water?
Water has a low specific heat capacity so large increases in heat energy cause a small temperature change.
Water is an excellent solvent for non-polar substances.
Covalent bonds between adjacent water molecules are responsible for its unique properties.
Water molecules are highly cohesive which is important for transport in xylem.
Which substance must be transported in the blood by lipoprotein complexes?
Cholesterol
Oxygen
Sodium chloride
Amino acids
Where do hydrogen bonds form?
Between the slight negative charge of hydrogen and slight positive charge of oxygen within a water molecule
Between the slight positive charge of hydrogen and slight negative charge of oxygen within a water molecule
Between the slight positive charge of hydrogen and slight negative charge of oxygen in different water molecules
Between the slight negative charge of hydrogen and slight positive charge of oxygen in different water molecules
Researchers have developed a skin patch which can detect and measure very small concentrations of ions, sugars, amino acids, proteins and hormones which remain when sweat evaporates. What allows the presence of these substances in sweat?
Cohesion
Hydrophobic interactions
Solvent properties
Thermal properties
At room temperature, water is a liquid and methane is a gas. Which molecular property explains this difference?
Higher molecular mass of water
Dipolarity of water
Presence of more hydrogen in methane
Higher boiling point of methane
Which property of water accounts for its moderating effects on the Earth’s atmosphere?
Cohesive
Thermal
Transparency
Adhesive
Which properties explain the ability of water to dissolve solutes?
I. Polarity of water molecules II. High specific heat capacity of water III. Hydrogen bonding
I and II only
I and III only
II and III only
I, II and III
Which molecule is depicted in the diagram?
A saturated Fatty Acid
An Unsaturated Fatty Acid
A trans fat
A vegetable oil
The table shows the range and classification of body mass index (BMI) values, as shown in the nomogram. What is the approximate reduction in body mass that a person of height 155cm and mass 95kg would have to lose to reach normal body mass? (remember, you can click on the image to see it better)
10kg
22kg
36kg
54kg
What distinguishes cellulose from glycogen and starch?
Only cellulose is found in plants.
Only cellulose is made up of glucose monomers.
Cellulose is far more branched than starch and glycogen.
Cellulose has a structural role whereas starch and glycogen function in energy storage.
The chart classifies individuals according to their height and mass. Based on the information provided, which individual is most at risk of diseases associated with the accumulation of excessive body fat?
Mass: 95kg, Height: 1.95m
Mass: 60kg, Height: 1.55m
Mass: 75kg, Height: 1.50m
Mass: 80kg, Height: 1.70m
The chart shows ranges of body mass index (BMI) for children and teenagers. A 9-year-old boy has a height of 120 cm and weighs 28.8 kg. What weight category is he in according to his BMI?
Underweight
Healthy
Overweight
Obese
Which of the molecules shown would be most suitable for long-term energy storage in humans?
What type of molecule is formed by the chemical reaction shown in the diagram?
Dipeptide
Disaccharide
Diglyceride
Cellulose
The diagram shows a type of fatty acid. What type of fatty acid is shown?
Trans unsaturated
Cis unsaturated
Trans saturated
Cis saturated
Which type(s) of fatty acid in the diet is/are positively correlated with an increased risk of coronary heart disease?
I. Saturated
II. Trans unsaturated
III. Cis unsaturated
I only
I and II only
II only
II and III only
Which molecule represents a lipid?
The Framingham heart study was an observational study that went on for 20 years. The following data were produced. Which conclusion can be drawn, based on these data?
It is better to eat margarine than to eat butter.
The more margarine consumed, the greater the incidence of coronary heart disease.
Butter is a natural product whereas margarine is hydrogenated vegetable oil that leads to coronary heart disease.
Margarine causes more heart related deaths than butter.
Which type of reaction is the breakdown of starch into sugars?
Denaturation
Reduction
Catabolic
Condensation
The diagram shows a molecular structure. Which type of molecule is shown?
Amino acid
Lipid
Carbohydrate
Nucleotide
How would you conduct an experiment on lactose and lactase to determine the ideal pH? You can google how you would alter the pH of milk. You'll need 10 steps.
What molecule is this?
Galactose
Glucose
Fructose
What molecule is this?
Glucose
Fructose
Galactose
What molecule is this?
Glucose
Galactose
Fructose
What molecule is this?
Lactose
Glucose
Maltose
Sucrose
What molecule is this?
Maltose
Lactose
Glucose
Sucrose
What molecule is this?
Sucrose
Lactose
Maltose
Glucose
What polysaccharide is this?
Glycogen
Starch
Cellulose
What polysaccharide is this?
Glycogen
Starch
Cellulose
What type of polysaccharide is this?
Starch
Glycogen
Cellulose
People who suffer from night blindness cannot see well at night because their retinal cells produce an abnormal form of a protein pigment. Which protein is this?
Fibrin
Myosin
Rhodopsin
Immunoglobulin
What is found in insulin molecules?
Phosphates
Nucleotides
Peptide bonds
Glycerol
The graph shows the results of an investigation into the activity of turnip peroxidase. The accumulation of the product of the reaction catalysed by the enzyme is shown at different pH values. Based on the data in the graph, what is most probably the optimum pH for turnip peroxidase?
Between 3 and 5
Between 10 and 11
Between 7 and 8
Between 9 and 10
Which statement correctly describes genome and proteome?
Only the genome but not the proteome can be analyzed using gel electrophoresis.
The genome and the proteome are the same in all tissues in an organism.
In cells of different tissues, the genome is the same while the proteome varies.
Only mutations in the proteome but not in the genome cause any variability.
Which protein has the highest tensile strength (ability to resist breaking when stretched)?
Cellulose
Actin
Spider Silk
Albumin
Which description matches the protein?
A
B
C
D
Which molecule could be hydrolyzed into amino acids?
How does the proteome of a species contain a larger number of proteins than genes that code for these proteins?
Some proteins have more than one polypeptide chain.
There are genes that code for several proteins.
Not all proteins are coded for by the genome.
Some proteins are coded for by other proteins.
The most abundant structural protein in the human body is found in ligaments and skin. What is the name of this protein?
Collagen
Hemoglobin
Myoglobin
Immunoglobulin
The graph shows enzyme activity plotted against temperature. What is the reason for the drop in enzyme activity above 40 °C?
A decrease in the enzyme concentration
Reaction is saturated because active sites are occupied
Insufficient activation energy for the reaction to proceed
Changes to the conformation of the enzyme
Which curve shows the concentration of product during the course of an enzyme-catalysed reaction?
A
B
C
D
Lactose can be removed from milk by passing the milk through a column of alginate beads to which immobilized lactase is bound. What is an advantage of immobilizing the enzyme?
It creates more active sites.
The alginate beads act as a coenzyme.
It lowers the activation energy of the reaction.
It allows the product to be separated easily from the enzyme.
Which statement applies to enzymes?
Enzyme function depends on collisions between substrate and active sites.
One active site typically binds to a broad range of substrates.
The active site on the substrate is specific to one enzyme.
When enzymes are immobilized they stop working.
Which enzyme is matched to its function?
Helicase forms a DNA helix
DNA polymerase forms a covalent bond between DNA nucleotides
restriction endonuclease seals nicks in recombinant DNA
Ligase unwinds the double helix.
What effect do changes in pH have on enzymes?
All enzymes increase in activity as pH increases.
The activity of all enzymes is reduced by a pH below or above 7.
Low pH causes reversible denaturation in all enzymes.
Extreme pH can alter the active site of all enzymes.
Lactose intolerance occurs when the enzyme, lactase, that digests lactose is not produced after infancy in humans. The incidence of lactose intolerance varies in different racial groups. The graph shows the distribution of lactose intolerance in different human populations. What can be hypothesized from the graph?
Native American people produce most lactase after infancy.
Most Indian people do not produce lactase after infancy.
Lactase is not produced after infancy in most Caucasian people.
One quarter of Afro-Caribbean people will probably experience digestive problems when drinking milk.
Living organisms control pH within their tissues. What is a reason for regulating pH?
All parts of a body must be kept at the same pH to survive.
Many reactions can only happen at specific pH levels.
pH affects osmosis.
Control of active transport is achieved by pH.
What is the advantage of using lactase in an immobilized state in the food manufacturing industry?
It functions within cells.
It dissolves in multiple solvents.
It converts cellulose into glucose.
It is less likely to become denatured.
Three flasks were prepared for an analysis of the activity of amylase. At time zero, each of the substances indicated in the diagrams was added. Which flask(s) could provide support for the hypothesis that heat denatures enzymes?
Flasks I and II after 15 minutes
Flasks II and III after 15 minutes
Flasks I and III after 15 minutes
Flask III at time zero and again after 15 minutes
The graph shows the effect of increasing the substrate concentration on the rate of an enzyme-catalysed reaction. What is occurring during the phase indicated by section Y of the graph?
The active site of the enzyme is saturated.
The enzyme becomes denatured.
The substrate concentration has risen too high.
The optimum rate is reached.
In an experiment the effect of changing pH on an enzymatic reaction is tested. Which could be a dependent variable in this kind of experiment?
Changing substrate concentration
Rate of formation of product
Variation in temperature
Change in pH
A fever in a normally healthy adult during an illness is not usually a problem and can be regarded as a defence mechanism. However, a fever higher than 41°C might be dangerous. What is the cause of the possible damage due to a high fever?
Loss of body mass
Muscle damage due to shivering
Overactive metabolic enzymes
Spread of infection
What is the minimum number of nucleotides needed to code for a polypeptide composed of 210 amino acids?
70
210
420
630
Which reaction occurs when a dipeptide is formed from amino acids?
Hydrolysis
Condensation
Transcription
Oxidation
A molecule of DNA is found to contain 200 guanine bases, representing 25 % of the total number of bases. How many phosphate groups does this molecule of DNA contain?
50
200
800
1000
What is a function of the enzyme helicase?
It coils DNA up into a double helical shape.
It links DNA nucleotides in a new DNA strand.
It breaks hydrogen bonds between the DNA strands.
It forms temporary hydrogen bonds to produce messenger RNA.
What is the correct arrangement for the components of one strand in a DNA molecule?
A
B
C
D
The data shows part of the genetic code for mRNA. Which anticodon could be found on a tRNA molecule bonded to lysine?
AAG
UUC
TTT
GAA
The hydrolysis of a pure sample of an organic molecule produces a pentose sugar, thymine, guanine and cytosine. What other substances could be expected to be present in the hydrolysed sample?
RNA
Uracil
Phosphate
ATP
Bacteria cultured in a medium containing only 15N were transferred to a medium containing only 14N and allowed to complete one round of replication. The DNA in bacteria produced as a result of replication on the 14N medium was extracted and subjected to caesium chloride centrifugation which separates DNA molecules according to their density. Which centrifuge tube shows the arrangement of bands observed after one round of replication?
Tube 3
Tube 4
Tube 5
Tube 6
Which feature is common to both mRNA and DNA?
Covalent bonds between adjacent nucleotides
Hydrogen bonds between guanine and cytosine
Ribose sugar attached to phosphate
Antiparallel arrangement of polynucleotide strands
What is the reason for Taq DNA polymerase being used in the polymerase chain reaction (PCR)?
It does not denature at high temperatures.
It produces Okazaki fragments more rapidly.
It allows translation to proceed rapidly.
It works efficiently with helicase in PCR.
The diagram represents transcription and translation. What structures do the letters X and Y represent?
X = DNA, Y = AntiCodon
X = mRNA, Y = AntiCodon
X = DNA, Y = codon
X = mRNA, Y = codon
For what did Meselson and Stahl’s work provide evidence?
The abiotic origin of organic molecules
The cell theory
The fluid mosaic model of membrane structure
The semi-conservative replication of DNA
The gene that codes for a particular polypeptide includes the base sequence shown.
GAGTACCCT
What is the base sequence of the mRNA molecule which is complementary to this sequence?
GAGTACCCT
CTCATGGGA
GUGTUCCCT
CUCAUGGGA
Where are amino acids joined together to make polypeptides?
Nucleus
Nucleolus
Golgi apparatus
Ribosomes
The table shows some codons for five amino acids. Which of these DNA strands will code for the amino acid sequence glycine-serine-glycine?
CCUUCGCCG
CCTTCGCCG
GGAAGCGGA
CCUUCGCCU
Nucleic acids are polymers of nucleotides. What parts of nucleotides are joined together in both DNA and RNA to make these polymers?
Large nitrogenous bases with small nitrogenous bases
Nitrogenous bases with hexose sugars
Nitrogenous bases with phosphates
Pentose sugars with phosphates
What do DNA replication, transcription and translation have in common?
Take place in cell nucleus
Require free nucleotides
Catalysed by polymerase
Complementary base pairing
Some yeast genes can be replaced by human genes that then continue to produce the same human proteins in the yeast cells. Which statement helps to explain this evidence?
The DNA of yeast and humans is identical.
Yeast and humans have the same number of chromosomes.
The genetic code is universal.
Yeast and humans are both eukaryotes.
For which discovery about DNA do Watson and Crick receive credit?
DNA is the molecule that genes are made of.
The amount of adenine equals the amount of thymine in an organism.
Phosphate–pentose bonding along the nucleotide backbone is covalent.
The shape of DNA is a double helix.
Which sequence of bases and amino acids could be produced by transcription and translation of the DNA molecule shown?
A
B
C
D
A short sequence of nucleotides reads GGACAGAGCGCAGACGA. In which type of molecule could this sequence be found?
DNA molecule only
RNA molecule only
Both in a DNA and an RNA molecule
In double-stranded DNA only
The table shows the genetic code.
Which mRNA could code for the sequence Met-Ser-Leu-Arg-Phe?
AUG UCA UCG UGG UUU
AUG UCC ACC AGA UUC
AUG UCU CCC AGA UUU
AUG UCG CUG AGG UUC
Meselson and Stahl conducted experiments using the isotopes 14N and 15N which showed that DNA replication is semi-conservative. What would they have observed about the distribution of isotopes in the DNA after one round of replication if DNA replication was conservative rather than semi-conservative?
Only 14N DNA
Only 15N DNA
All DNA half 14N and half 15N
Half the DNA with only 14N and half with only 15N
Which are necessary to make DNA replication semi-conservative?
I. Separation of the strands by RNA polymerase
II. Complementary base pairing
III. Use of a pre-existing strand as a template
I and II only
I and III only
II and III only
I, II and III
What is a similarity between DNA and RNA?
Both are polymers of nucleotides.
Both are composed of antiparallel strands.
Both contain adenine, cytosine and thymine.
Both contain ribose sugar.
What enables bacteria to produce human growth hormone?
DNA replication is semi-conservative.
The polymerase chain reaction can be used.
They need the hormone for growth.
The genetic code is universal.
The graph shows the changes in lactate measured in an athlete’s blood during exercise. Which hypothesis provides the most likely explanation for the curve?
As exercise intensity increases, lactate is converted back to glucose.
Anaerobic exercise results in high levels of lactate.
Lactate provides energy for intense exercise.
Under anaerobic conditions the body produces less lactate.
A respirometer is used to measure the oxygen consumption of germinating seeds. The distance that the oil drop moves is measured at 15-minute intervals. What is the function of chemical X?
Absorbs carbon dioxide so the oxygen released by the seeds can be measured
Absorbs carbon dioxide so the oxygen absorbed by the seeds can be measured
Absorbs oxygen so the carbon dioxide released by the seeds can be measured
Absorbs oxygen so the carbon dioxide absorbed by the seeds can be measured
What is a difference between aerobic respiration and anaerobic respiration in yeast?
Anaerobic respiration requires enzymes, aerobic respiration does not.
Anaerobic respiration requires glucose, aerobic respiration does not.
Anaerobic respiration produces ethanol, aerobic respiration does not.
Anaerobic respiration does not produce oxygen, aerobic respiration does.
The graph shows the results of an experimental investigation that compared the rates at which lactose, glucose and galactose are broken down in the process of anaerobic cellular respiration by the yeast Torulopsis cremoris. What can be concluded from these results?
Cellular respiration of lactose involves the production of glucose and galactose.
The breakdown of glucose and galactose occurs more slowly in the presence of lactose.
The rate of cellular respiration is greater for glucose than for lactose and galactose.
The percentage of sugar remaining after 42 hours is greater for galactose than glucose.
The diagram shows a respirometer. What solution should be in the bottom of each tube and in which direction will the manometer fluid move?
Solution placed in the bottom of each tube: acid; direction of movement of fluid in the manometer: up on the left side
Solution placed in the bottom of each tube: alkali; direction of movement of fluid in the manometer: down on the right side
Solution placed in the bottom of each tube: acid; direction of movement of fluid in the manometer: up on the right side
Solution placed in the bottom of each tube: alkali; direction of movement of fluid in the manometer: down on the left side
Which compound is a waste product of anaerobic respiration in humans?
Carbon dioxide
Ethanol
Lactate
Pyruvate
The diagram shows a respirometer used to measure respiration rate in germinating seeds. What is the expected direction of movement of the fluid at X and the function of the fluid at Y?
X= down, Y=absorb CO2
X= down, Y=produce CO2
X= up Y=absorb CO2
X= down, Y=absorb O2
Yeast cells, Saccharomyces cerevisiae, were incubated with and without glucose at three different temperatures for a period of four minutes, during which the rate of CO2 production was measured with a CO2 sensor. What conclusion can be drawn from the results of this experiment?
Yeast uses lipids rather than glucose in respiration at low temperatures.
Addition of glucose has a greater impact on rates of cell respiration at lower temperatures.
Rates of cell respiration increase with temperature.
More glucose is produced at higher temperatures.
Which process causes ADP to change to ATP?
Hydrolysis
Protein synthesis
DNA replication
Anaerobic cell respiration
The graph shows the changes in lactate and pyruvate measured in an athlete’s blood during and following a mild exercise period as compared to the period before the exercise. What do these curves suggest?
Before the exercise, there was no pyruvate produced because there was no cell respiration.
During the exercise, there was not enough oxygen available for cell respiration, so the process was partly anaerobic.
During the exercise, the level of lactate increased due to aerobic respiration.
After the exercise, the level of lactate decreased because there was enough pyruvate to be used for anaerobic cell respiration.
Which pair of molecules are products of aerobic and anaerobic cell respiration in some organisms?
A
B
C
D
The graph shows how the rate of photosynthesis of a green plant varies with CO2 concentration at two different light intensities. The temperature is kept constant at 20 °C. What is the limiting factor at X?
Chlorophyll
Light intensity
Temperature
CO2 concentration
The apparatus shown was used to investigate the effect of varying carbon dioxide concentration on the rate of photosynthesis. Carbon dioxide concentrations were varied by adding different amounts of sodium hydrogen carbonate (NaHCO3) to water. What is the dependent variable in this investigation?
Temperature
Light intensity
Amount of NaHCO3 added
Volume of oxygen produced
What prevents plants from converting carbon dioxide into glucose in the dark?
They do not have a source of energy.
It is too cold.
They do not require glucose during the night.
Their enzymes are inhibited.
If a plant is exposed to light, which colour of light would lead to the lowest rate of oxygen release by a green plant?
Blue
Red
Green
White
What does the Rf value in thin-layer chromatography represent?
The distance travelled by the pigment front in a fixed time period
The distance from the origin to the solvent front at the end of the experiment
The ratio of distances travelled by the pigment and solvent fronts
The concentration of the pigment applied to the chromatography plate
Plants produce carbon dioxide in respiration and use carbon dioxide in photosynthesis. The graph shows the volume of carbon dioxide exchanged in a plant at different light intensities. What is shown by the graph?
There is no photosynthesis between W and X.
There is no photosynthesis between Y and Z.
There is more respiration than photosynthesis between Y and Z.
There is more respiration than photosynthesis between W and X.
The graph shows the effect of increasing light intensity on the rate of CO2 uptake by a species of green plant maintained in conditions of constant temperature and CO2 concentration. Which statement is consistent with the graph?
Photosynthesis stops at high light intensity.
Rates of photosynthesis increase with temperature.
Cell respiration leads to net production of CO2 at low light intensity.
There is a negative correlation between CO2 uptake and light intensity.
The graph shows the absorption spectra of chlorophyll a and chlorophyll b. What can be concluded from the graph?
Both chlorophyll a and chlorophyll b absorb a large amount of green light
Chlorophyll b absorbs red light more efficiently than blue light
Other pigments must absorb light between blue and red in the spectrum
Chlorophyll a and chlorophyll b have different absorption peaks
The graph shows the relationship between rate of photosynthesis and light intensity as influenced by both temperature and CO2 concentration. What conclusion can be drawn from the data in the graph?
CO2 is always the limiting factor at low light intensities and temperatures.
Light intensity is only the limiting factor at high light intensities.
Temperature is only the limiting factor at high light intensities and CO2 concentrations.
Both temperature and light intensity are limiting factors at 660 ppm CO2 and less than 200 W m–2 light intensity.
An experiment was set up so that each test tube contained water at a pH of 6.3 and a pH indicator. Test tubes 1 and 2 also contained a common pond autotroph. Carbon dioxide dissolves in water and forms carbonic acid. After three days the four test tubes were found to have these results. What conclusion can be drawn from test tube 1 and test tube 2?
Test tube #1: photosynthesis has used CO2, test tube #2: respiration has produced CO2
Test tube #1: photosynthesis has made the water more acidic, test tube #2: respiration has made the water less acidic
Test tube #1: photosynthesis occurred but not respiration, test tube #2: respiration occurred but not photosynthesis
No conclusion can be drawn, since pH in the controls has changed.
What is the relative wavelength in the visible spectrum of red light and blue light and are these colours absorbed or reflected by chlorophyll?
A
B
C
D
The fungus Rhytisma grows on the leaves of certain trees, causing a yellow leaf area in which chlorophyll is no longer present. A black, tar-like stain later spreads out. What happens in the leaf when Rhytisma is present?
I. An increase in the intake of carbon dioxide
II. A reduction in the production of oxygen
III. An increase in the loss of water
I only
II only
II and III only
I, II and III
