WorksheetsA level Biology AQA Unit 4
Total questions: 32
Worksheet time: 39mins
The ecological role (1) of hermit crabs (2) includes scavenging in rock pools (3).
What ecological terms are represented by the numbers 1, 2 and 3?
A
B
C
D
Limiting factors affect population size. Which of these factors acts independently of the density of the population?
air temperature
disease
food supply
territory size
An experimental pond was set up by placing water containing a little plant fertilizer in a tank and leaving it outside. Various organisms, X, Y and Z, were subsequently found in the tank and their inter-relationships were observed. The graph shows how their populations changed over time. Which line identifies the trophic levels of X, Y and Z?
A
B
C
D
Which of the following bonds are broken during DNA replication?
hydrogen bonds between bases
phosphodiester bonds
covalent bonds between bases
ionic bonds between bases and phosphate groups
Which technique was used to determine the double-helical structure of DNA?
electrophoresis
chromatography
centrifugation
X-ray crystallography
Analysis of a molecule of DNA found it to contain 200 adenine bases, 20% of the total number of bases in the strand.
How many phosphate groups did it contain?
200
400
800
1000
Thymine comprised 36% of the nitrogen bases present in a sample of double stranded DNA.
What was the percentage of guanine in the sample?
14
28
36
64
Foot and mouth disease virus (FMDV) is the pathogen that causes foot and mouth disease in livestock.
An analysis of the genetic material of the ‘O’ strain of FMDV showed that it contains 1996 adenine bases, 2131 guanine bases, 1642 uracil bases and 2365 cytosine bases.
Which one of the following describes the genetic material of the virus?
single-stranded DNA
single-stranded RNA
double-stranded DNA
double-stranded RNA
In which stage of meiosis are chiasmata formed?
prophase 1
anaphase 1
prophase 2
telophase 2
Why is the formation of chiasmata an important feature of meiosis?
It ensures that the same genetic characteristics appear in daughter cells as in the parent.
It ensures that the number of genes in the new chromosomes changes to produce variation.
It provides opportunities for new genotypes to arise.
It prevents homologous chromosomes from pairing.
What do we call a sequences, within a gene that code for an amino acid sequence.
intron
exon
A gene is a base sequence of DNA that codes for (click all that are correct):
the amino acid sequence of a polypeptide
introns
a functional RNA (including ribosomal RNA and tRNAs)
Which molecule is shown here?
mRNA
DNA
tRNA
ATP
What is transcription?
process of semi-conservative replication of DNA
the production of polypeptides from the sequence of codons carried by mRNA
the production of mitochondrial DNA
the production of mRNA from DNA
What is translation?
process of semi-conservative replication of DNA
the production of polypeptides from the sequence of codons carried by mRNA
the production of mitochondrial DNA
the production of mRNA from DNA
The diagram represents one process that occurs during protein synthesis. Name the process.
(a)
In the diagram, the first codon is AUG. Give the base sequence of the complementary DNA base sequence.
(a)
In the diagram, the first codon is AUG. Give the base sequence of the missing anticodon.
(a)
What is the name of a position of a gene on a chromosome?
(a)
A geneticist investigated genetic diversity in four different breeds of dog. She compared DNA base sequences of the same genes from a large number of dogs from each breed.The geneticist calculated the mean genetic diversity for each breed of dog.
The value of this mean was between 0 and 1.
A mean value of 1 shows maximum genetic diversity.
A mean value of 0 shows no genetic diversity.
Her results are shown in the table.
Which breed has the greatest diversity?
Airedale Terrier
Bull Terrier
Jack Russel Terrier
Miniature Terrier
A geneticist investigated genetic diversity in four different breeds of dog. She compared DNA base sequences of the same genes from a large number of dogs from each breed.The geneticist calculated the mean genetic diversity for each breed of dog.
The value of this mean was between 0 and 1.
A mean value of 1 shows maximum genetic diversity.
A mean value of 0 shows no genetic diversity.
Her results are shown in the table.
Which breed is the most inbred?
Airedale Terrier
Bull Terrier
Jack Russel Terrier
Miniature Terrier
The table shows part of the DNA base sequence coding for a gene. What is the maximum number of amino acids for which this base sequence could code?
3
4
6
12
Phenylketonuria is a disease caused by mutations of the gene coding for the enzyme PAH. The table shows part of the DNA base sequence coding for PAH. It also shows a mutation of this sequence which leads to the production of non-functioning PAH. How does this mutation lead to the formation of non-functioning PAH? Select all that apply.
Change in amino acid sequence
The enzyme is denatured
Change in hydrogen bonds alters tertiary structure
Translation will not occur
What do we call a group of organisms that are able to produce fertile offspring?
(a)
What is species richness?
the number of different species in a community
the number of different species in a population
the number of organisms in a population
the genetic diversity within a population
Scientists investigated the species richness of fish caught at various depths in the Pacific Ocean close to the western coast of Chile.The graph shows the scientists’ results. What is the modal value for species richness?
(a)
The table shows the classification of the long tailed field mouse. Write the correct word for box 1.
(a)
The table shows the classification of the long tailed field mouse. Write the correct word for box 2.
(a)
The table shows the classification of the long tailed field mouse. Write the correct word for box 3.
(a)
Figure 1 shows the life cycle of a moss plant. In this life cycle, only the stalk and spore capsule are diploid. All the cells in all the other stages of the life cycle of the moss are haploid.Which letter shows where meiosis occurs in the life cycle of the moss?
A
B
C
D
Patau syndrome is a condition caused by a mutation affecting chromosome number. All the cells of the body will have this mutation. The diagram shows the chromosomes from one of the cells of a female who has Patau syndrome. What caused the change in chromosome number?
Homologous chromosomes did not separate in mitosis
Homologous chromosomes did not separate in meiosis
The mother did not have an x chromosome
Crossing over
A student investigated the effectiveness of four different concentrations, A, B, C and D, of the same disinfectant on the growth of a bacterium. He grew a culture of this bacterium on nutrient agar (a solid growth medium) in a Petri dish. The student then cut out four filter paper discs and soaked each disc in one of the four concentrations. He then placed the discs on the nutrient agar in the Petri dish. He then left the Petri dish at 25 °C for 24 hours.The diagram shows the appearance of the Petri dish after 24 hours. Which is the most effective concentration?
A
B
C
D
