Human Cells

Human Genome

The Human Genome consists of DNA nucleotides whose sequence depends on the bases that each nucleotide has. Genes are specific sequences that contain exon and intron sequences. Exons are coding and introns are non-coding. The rest of the DNA sequences do not code for proteins.

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Multiple Choice

The genetic code for proteins is copied into what molecule?

• rRNA

• tRNA

• mRNA

Multiple Choice

mRNA sequence contains a triplet of bases known as a..

• Anti-codon

• Codon

• Amino acid

Multiple Choice

The triplet of bases on tRNA that is complementary to the mRNA triplet is known as...

• Anti-codon

• Codon

• Amino Acid

Mutations

Mutations can have two results:

• no protein is expressed

• an altered protein is expressed

Types of Mutations

• the substitution of one nucleotide with another

• the insertion of one or more nucleotides into a DNA sequence

• the deletion of one or more nucleotides from a sequence

Multiple Choice

What type of mutation is there in this example?

• Missense

• Nonsense

• Frameshift

• Deletion

Multiple Choice

What would be the effect of a missense mutation?

• Shorten the protein product

• Change the amino acid

• Create a shift in the reading frame

Multiple Choice

Using the DNA sequence, what would happen to the protein product if the 6th base was replaced by a guanine?

• Change of amino acid

• Creates a STOP codon

• The shape is altered

• A shortened product is produced

Chromosomal Mutations

​Mutations can also affect chromosomes rather than nucleotides

Types of chromosomal mutations:

• deletion is where a section of a chromosome is removed.

• translocation is where a section of a chromosome is added to another chromosome that is not its homologous partner.

• inversion is where a section of a chromosome is reversed.

• duplication occurs when a section of a chromosome is added from its homologous partner.

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Multiple Choice

What happens during translocation?

• A section of chromosome is removed

• A section of chromosome is inverted

• A section is moved from one chromosome to it's homologous partner

Multiple Choice

The diagram below shows a metabolic pathway that is controlled by feedback inhibition. For Substance 4 to bring about end product inhibition, with which of the following would it interact?

• Substance 1

• Substance 3

• Enzyme 1

• Enzyme 3

Multiple Choice

Which type of inhibition involves an early enzyme in a metabolic pathway being inhibited?

• Feedback

• Competitive

• Non-competitive

Multiple Choice

Which type of reaction requires energy?

• Anabolic

• Catabolic

Enzyme Inhibition

Enzymes have two types of inhibitors: competitive or non-competitive

• competitive binds to the active site

• non-competitive binds to a site on the enzyme other than the active site

Inhibitor binding to enzyme causes the active site to change shape

Effects can't be overcome by increasing substrate conc

Non-competitive inhibitor

Inhibitor is a similar shape to substrate

Effects can be overcome by increasing substrate conc

Competitive inhibitor

Enzyme inhibition

Multiple Choice

What type of inhibition does enzyme B show?

• Competitive

• Non-competitive

Aerobic Respiration

​Aerobic respiration occurs in cells to produce ATP which can then be used as for reactions. It can be split into three stages:

• Glycolysis

• Citric Acid Cycle

• Electron Transport chain

Multiple Choice

What is the location of each stage?

• Glycolysis: matrix of the mitochondrion

  Citric Acid cycle: Cytoplasm

  Electron transport chain: inner membrane of the mitochondrion

• Glycolysis: cytoplasm

  Citric Acid cycle: inner membrane of the mitochondrion

  Electron transport chain:

  matrix of the mitochondrion

• Glycolysis: matrix of the mitochondrion

  Citric Acid cycle: inner membrane of the mitochondrion

  Electron transport chain:

  cytoplasm

• Glycolysis: cytoplasm

  Citric Acid cycle: matrix of the mitochondrion

  Electron transport chain: inner membrane of the mitochondrion

Multiple Choice

As H+ ions are pumped across the membrane in the electron transport chain, which molecule is produced?

• oxygen

• ATP

• Electrons

• NADH

Multiple Choice

What is the final hydrogen acceptor that then produces a molecule of water?

• ATP

• CO2

• Oxygen

• Electrons

Multiple Choice

During each of the stages of respiration, H+ ions and high energy electrons are removed from the intermediates. Where do these go?

• NAD Carrier

• Blood Stream

• ATP