Topic 3 - Genetics

Question 1

Which structures are found inside the nucleus?

Answer 1

chromosomes

Question 2

Which substance forms a long strand in each chromosome?

Answer 2

DNA

Question 3

How do body cells make copies of themselves?

Answer 3

cell division, mitosis

Question 4

How many chromosomes are there in a human body cell nucleus?

Answer 4

46

Question 5

What happens in fertilisation?

Answer 5

two gametes fuse

Question 6

What is the name of the cell formed in fertilisation?

Answer 6

zygote, fertilised egg cell

Question 7

Which term means producing more of the same kind of organism?

Answer 7

reproduction

Question 8

What is the name of the human male gamete?

Answer 8

sperm cell

Question 9

The DNA strand in a chromosome contains sections that carry instructions for characteristics. What are these sections called?

Answer 9

genes

Question 10

What molecule forms the genome of an organism?

Answer 10

DNA

Question 11

Where are genes found?

Answer 11

[in sections of DNA] on chromosomes

Question 12

What does a gene carry the instructions for?

Answer 12

making a protein

Question 13

A protein is made by linking together smaller molecules. What are these smaller molecules called?

Answer 13

amino acids

Question 14

What is any molecule made of repeating units called?

Answer 14

a polymer

Question 15

A human cell contains 46 strands of DNA. Is it diploid or haploid?

Answer 15

diploid

Question 16

Are the cells produced by meiosis haploid or diploid?

Answer 16

haploid

Question 17

Are the cells produced by mitosis haploid or diploid?

Answer 17

diploid

Question 18

What shape is DNA?

Answer 18

a double helix

Question 19

What is a chromosome made out of?

Answer 19

DNA and proteins [to package the DNA]

Question 20

What shape is a DNA molecule?

Answer 20

double helix

Question 21

What part of a DNA strand contains the instructions for a protein?

Answer 21

gene

Question 22

What are the letters of the bases that form the DNA code?

Answer 22

A,C,T and G

Question 23

How do these bases pair up in DNA?

Answer 23

A with T, C with G

Question 24

Apart from bases, what other parts are needed in a DNA molecule?

Answer 24

phosphate group, sugar

Question 25

What is one phosphate group, one sugar and one base called?

Answer 25

nucleotide

Question 26

Why is DNA a polymer?

Answer 26

It is made of many nucleotides joined in a chain.

Question 27

Give an example of a protein.

Answer 27

any example. E.g. an enzyme

Question 28

How is the active site of an enzyme formed?

Answer 28

by folding of protein/polypeptide/amino acid chains

Question 29

Why are proteins polymers?

Answer 29

They are made of many amino acids joined in a chain.

Question 30

How many bases does a codon ( contain?

Answer 30

three

Question 31

How are Hydrogen bonds formed

Answer 31

Parts of DNA bases have a very slight electrical charges. A slightly negatively charged base attracts a slightly positively charged base.

Question 32

A change in the bases of a gene creates a genetic variant. What is this sort of change called?

Answer 32

mutation

Question 33

How many bases does a codon (a sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.) contain?

Answer 33

three

Question 34

What is an organism’s phenotype?

Answer 34

its observed characteristics

Question 35

What are different versions of the same gene called?

Answer 35

alleles

Question 36

What sort of variation do alleles cause in organisms?

Answer 36

genetic variation

Question 37

When we consider one gene, what word is used to say that both alleles are the same?

Answer 37

homozygous

Question 38

If a dominant allele has the letter A, how would you show that an organism is heterozygous?

Answer 38

Aa

Question 39

What word describes the characteristics caused by the alleles of a gene?

Answer 39

phenotype

Question 40

What word describes the alleles of a gene found in an organism?

Answer 40

genotype

Question 41

What word describes an allele that only has an effect if an organism has two copies?

Answer 41

recessive

Question 42

A genotype is written QQ. What does this tell you?

Answer 42

It is homozygous for the dominant allele.

Question 43

What is a probability?

Answer 43

the chance of an event occurring

Question 44

If the occurrence of an event has a probability of 1, what does this mean?

Answer 44

It is certain to occur.

Question 45

How can we show the possible inheritance of alleles by offspring from their parents?

Answer 45

genetic diagram, Punnett square

Question 46

Which type of diagram is used to show the inheritance of a characteristic through different generations in a family?

Answer 46

family pedigree

Question 47

If the genotype for one gene of a rabbit is Bb, where B is the allele for brown coat and b the allele for black coat, what is the rabbit’s phenotype?

Answer 47

brown

Question 48

What are the possible allele combinations of offspring from heterozygous parents who are both Aa for a gene?

Answer 48

AA, Aa and aa

Question 49

A human egg cell that contains an X sex chromosome is fertilised by a sperm cell containing a Y sex chromosome. What will be the sex of the baby that develops?

Answer 49

male

Question 50

What is the theoretical probability of a couple having a baby boy?

Answer 50

probability 50 per cent or half