7.4 Genes & Proteins

Question 1

Alleles are…

Answer 1

An alternative form of a gene

Question 2

Human DNA is arranged in the form of…

Answer 2

23 pairs chromosomes

Question 3

We receive one set of chromosomes from our father and the other from our…

Answer 3

Mother

Question 4

Diploid is a cell, nucleus or organism in which the nuclei contain…

Answer 4

Two copies of each chromosome - 46

Question 5

Haploid is a cell, nucleus or organism in which the nuclei contains…

Answer 5

Just one set of chromosomes - 23

Question 6

Each cell has…

Answer 6

Homologous pairs of chromosomes

Question 7

A gene is…

Answer 7

A section of DNA that carries coded information about a characteristic

Question 8

Genes occur at the same relative position or…

Answer 8

Locus on homologous chromosomes

Question 9

These paired chromosomes are not completely identical, but they…

Answer 9

Carry the same genes

Question 10

Each of the homologous pair of chromosomes has a different allele for eye colour from the other, in this way, genes influence the…

Answer 10

Phenotype or characteristics of an organism

Question 11

Phenotype is…

Answer 11

The characteristics of an organism resulting from its alleles

Question 12

The allele that codes for cystic fibrosis has…

Answer 12

3 nucleotides missing - codon, anticodon

These 3 nucleotides code for one amino acid

Question 13

The CF allele produces a protein that is exactly the same as the normal protein except for one…

Answer 13

Amino acid which is significant

Question 14

Proteins form a…

Answer 14

Complex tertiary structure - bonds form between R groups in the amino acids that hold the protein in this specific tertiary structure

Question 15

The faulty CFTR protein produced by the CF allele is a different shape because just one…

Answer 15

Amino acid is missing - cannot function properly

Question 16

Many genes code for proteins that act as…

Answer 16

Enzymes

Question 17

The shape of the active site depends on the tertiary structure of the protein which in turn depends on the…

Answer 17

Order of the amino acids - which is dependant on the sequence of bases in the DNA molecule

Question 18

Different alleles have slightly different…

Answer 18

Base sequences in the DNA - this means that they produce a protein with a slightly different sequence of amino acids and so the enzyme has a different tertiary structure.

Question 19

This means that the enzymes may have an…

Answer 19

Altered active site and so cannot form an ESC with its substrate anymore

Question 20

Garrod studied…

Answer 20

Alkaptonuria

Question 21

People with this disorder cannot break down a substance called…

Answer 21

Homogentisic acid

Question 22

Homogentisic acid accumulates in the…

Answer 22

Tissues and is excreted in urine

Question 23

It is detected easily because the …

Answer 23

Molecule oxidises into a black product which means that the urine is dark in colour

Question 24

The black product also accumulates in places such as…

Answer 24

The sclera of the eye and the cartilage of the ear and nose

Question 25

Garrod added the amino acids…

Answer 25

Phenylalanine and tyrosine to the diet

Question 26

When these amino acids were added he noticed that…

Answer 26

Homogentisic acid increased in the urine of people with alkaptonuria but not in normal individuals

Question 27

Garrod concluded that hereditary information controls…

Answer 27

Chemical reactions in the body - he decided that the disorder was the result of faulty metabolism

Question 28

We now know that people with this disorder have an allele that …

Answer 28

Produces a faulty enzyme - cannot convert homogentisic acid to maleylacetoacetate

Question 29

What is a metabolic pathway?

Answer 29

A sequence of reactions leading to a product.

Controlled by enzymes.

Question 30

What is meant by homologous chromosomes ?

Answer 30

Chromosomes with same genes