B3 - Genetics - Year 11

Question 1

What is produced in meiosis?

Answer 1

4 genetically different haploid cells

Question 2

How many chromosomes are there in a haploid cell?

Answer 2

23

Question 3

What is the structure of DNA?

Answer 3

A polymer made up of two strands coiled to form a double helix

Question 4

What are the strands of DNA made from?

Answer 4

A series of complementary base pairs

Question 5

What holds the strands of DNA together?

Answer 5

Weak hydrogen bonds

Question 6

What is the complementary base pair of cytosine (C)?

Answer 6

Guanine (G)

Question 7

What is the complementary base pair of guanine (G)?

Answer 7

Cytosine (C)

Question 8

What is the complementary base pair of adenine (A)?

Answer 8

Thymine (T)

Question 9

What is the complementary base pair of thymine (T)?

Answer 9

Adenine (A)

Question 10

What is the genome of an organism?

Answer 10

All the genetic material of an organism

Question 11

What is a gene?

Answer 11

A section of a DNA molecule that codes for a specific protein

Question 12

Why is protease added when extracting DNA?

Answer 12

Protease breaks down proteins in the nuclear membrane and destroys enzymes that may break down the DNA

Question 13

Why is fruit crushed in the extraction of DNA?

Answer 13

To break down cell walls

Question 14

Why is detergent added in the extraction of DNA?

Answer 14

To break down cell membrane

Question 15

Why is salt added in the extraction of DNA?

Answer 15

To clump the DNA together

Question 16

What are the stages of extracting DNA from fruit?

Answer 16

Crush and add washing up liquid and salt and water, add protease, heat and filter, pour ice cold ethanol into the filtrate

Question 17

Why is ice cold ethanol used in the extraction of DNA?

Answer 17

To precipitate the DNA (DNA is insoluble in ethanol)

Question 18

Why is filtration used in the extraction of DNA?

Answer 18

To remove insoluble material

Question 19

What is an allele?

Answer 19

A version of a gene

Question 20

What are the two types of allele?

Answer 20

Dominant and recessive

Question 21

What does homozygous mean?

Answer 21

There are two copies of the same allele

Question 22

What does heterozygous mean?

Answer 22

There is one dominant and one recessive allele

Question 23

Which genetic term describes the physical characteristics of an individual?

Answer 23

Phenotype

Question 24

What is a gamete?

Answer 24

A sex cell that has a haploid nucleus

Question 25

What is a zygote?

Answer 25

A fertilised egg cell

Question 26

What is the genotype of a female?

Answer 26

XX

Question 27

What is the genotype of a male?

Answer 27

XY

Question 28

Give two types of variation that influence phenotype

Answer 28

Genetic variation and environmental variation

Question 29

Give benefits of discovering the sequence of bases for all plants and animals

Answer 29

Identify useful genes, track evolution, understand diseases, discover new medicines, identify sequences that allow organisms to cope with environmental change

Question 30

How has the Human Genome Project contributed to advances in medicine?

Answer 30

Genes on human chromosome identified, faulty genes can be identified, people can be tested for a genetic disorder, development of gene therapy, personalised medication/counselling can be given

Question 31

What causes genetic variation?

Answer 31

Mutation and sexual reproduction

Question 32

What causes environmental variation?

Answer 32

An organism’s environment

Question 33

Do most genetic mutations affect the phenotype?

Answer 33

No, some may have a small effect and rarely a single mutation will significantly affect the phenotype.