B12b Inheritance

Question 1

What are gametes?

Answer 1

Sex cells
Haploid (half number of chromosomes)

Question 2

What is a chromosome?

Answer 2

A long coiled molecule of DNA that carries genetic information

Question 3

Define the term gene?

Answer 3

A small section of DNA on a chromosome
Codes for a particular sequence of amino acids to make a specific protein

Question 4

What is an allele?

Answer 4

Different versions of the same gene

Question 5

What is a dominant allele?

Answer 5

A version of a gene where only one copy is needed for it to be expressed.

Question 6

What is a recessive allele?

Answer 6

A version of a gene where two copies are needed for it to be expressed

Question 7

What is meant when an organism is homozygous?

Answer 7

When an organism has two copies of the same allele

(2 recessive or 2 dominant alleles)

Question 8

What is meant when an organism is heterozygous?

Answer 8

When an organism has two different versions of the same gene.

Question 9

What is the genotype?

Answer 9

The alleles present at a particular gene

Determine the phenotype of an organism

Question 10

What is a phenotype?

Answer 10

The visible characteristic

Question 11

Name the gametes found in plants

Answer 11

Pollen
Egg

Question 12

Name the gametes in animals

Answer 12

Sperm
Egg

Question 13

Name the type of cell division used to make gametes

Answer 13

Meiosis

Question 14

How many chromosomes are found in human body cells?

Answer 14

46

Question 15

How many chromosomes are found in human gametes?

Answer 15

23

Question 16

How are dominant and recessive alleles shown in a genetic diagram?

Answer 16

Dominant - capital letter
Recessive - lower case letter
The same letter is used for the gene

Question 17

Give an example of a characteristic which is controlled by a single gene

Answer 17

Fur colour in mice
Red green colour blindness in humans

Question 18

Most characteristics are the result of multiple genes rather than a single gene. True or false?

Answer 18

True

Question 19

What is meant by an inherited disorder?

Answer 19

Caused by the inheritance of certain alleles

Question 20

Give an example of a genetic condition caused by a dominant allele

Answer 20

Polydactyly

Question 21

Describe the phenotype shown by a person with polydactyly

Answer 21

Extra fingers or toes

Question 22

Give an example of a genetic condition caused by a recessive allele

Answer 22

Cystic fibrosis

Question 23

Give the genotype for a person with cystic fibrosis

Answer 23

ff

Question 24

Give the possible genotypes of a person with polydactyly

Answer 24

DD
Dd

Question 25

Give the genotype of a human female

Answer 25

XX

Question 26

Give the genotype of a human male

Answer 26

XY

Question 27

What are the sex chromosomes?

Answer 27

A pair of chromosomes that determine sex

Question 28

What is sexual reproduction?

Answer 28

Type of reproduction There is mixing of genetic information from two parents Involves gametes made by meiosis The offspring show variation

Question 29

What is asexual reproduction?

Answer 29

Type of reproduction Only one parent involved No mixing of genetic information Only mitosis is involved All the offspring a re genetically identical (clones)

Question 30

What happens to the number of chromosomes in the cells produced by meiosis?

Answer 30

Halved

Question 31

Describe the events that take place in meiosis

Answer 31

The genetic material is copied (DNA replicated) Cell divides twice to form 4 gametes Each gamete has a single set of chromosomes All gametes are genetically different

Question 32

Name the organs where meiosis takes place

Answer 32

Male - testis Female - ovary

Question 33

The B allele produces brown eyes The b allele produces green eyes Give the genotypes of a person with brown eyes

Answer 33

BB or Bb

Question 34

The B allele produces brown eyes The b allele produces green eyes What percentage of the offspring will have brown eyes

Answer 34

75%

Question 35

The B allele produces brown eyes The b allele produces green eyes What is the genotype of a person with green eyes?

Answer 35

bb

Question 36

What proportion of the offspring will have purple flowers?

Answer 36

75%

Question 37

What colour flower is produced by the homozygous recessive?

Answer 37

White flower

Question 38

What is the genotype of a female child?

Answer 38

XX

Question 39

What is the ratio of male and female offspring on this Punnett square

Answer 39

1:1

Question 40

Describe the shape of a DNA molecule

Answer 40

Double helix

Question 41

What does the term genome mean?

Answer 41

The entire genetic material of that organism

Question 42

Where is the genetic material found in a cell?

Answer 42

Nucleus Chromosomes

Question 43

Name the chemical found in the genetic material

Answer 43

DNA

Question 44

Describe the structure of DNA

Answer 44

A polymer Made of two strands Forms a double helix

Question 45

Why is the understanding the human genome important?

Answer 45

Search for genes linked to different disease Understand an treat inherited disorders Trace human migration patterns in the past

Question 46

What are the advantages of using the human genome?

Answer 46

Search for genes that cause disease Treatment of genetic disorders Tracing human migration patterns from the past

Question 47

Describe the shape of this molecule

Answer 47

Double helix

Question 48

Name this molecule

Answer 48

DNA