Inheritance and Variation- Paper 2 Flashcards Preview

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Flashcards in Inheritance and Variation- Paper 2 Deck (45)
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1
Q

By which cell division type does asexual reproduction rely on?

A

Mitosis

2
Q

How are gametes formed?

A

Meiosis

3
Q

How is a gamete different from a normal body cell?

A

Half genetic information - haploid

4
Q

Name the structure formed by fertilisation (fusion of male and female gametes).

A

Zygote

5
Q

State one difference between asexual and sexual reproduction.

A

A: no fertilisation/genetically identical offspring; S: fertilisation/genetic variation

6
Q

Name the gametes in plants.

A

Egg + Pollen

7
Q

Name the organ that produces egg cells.

A

Ovaries

8
Q

Name the organ that produces sperm cells.

A

Testes

9
Q

How many divisions do a cell undergo in meiosis?

A

Twice

10
Q

Name the process where a sperm and an egg cell fuse together.

A

Fertilisation

11
Q

How many chromosomes are there in a human gamete?

A

23

12
Q

Define ‘gametes’.

A

Sex cells

13
Q

Name the gametes in animals.

A

Sperm & egg

14
Q

Describe the cells produced by meiosis.

A

4 cells, genetically different.

15
Q

Describe the cells produced by mitosis.

A

2 cells, genetically identical (clones).

16
Q

State the three key steps in meiosis.

A
  1. Copies of the DNA are made.
  2. The cell divides twice to form 4 gametes, each with a single set of chromosomes.
  3. All 4 cells are genetically different from each other.
17
Q

When a new cell is formed through fertilisation, how does it divide?

A

Mitosis.

18
Q

The genetic material in the nucleus of a cell is?.

A

DNA

19
Q

Describe the structure of DNA.

A

A polymer made up of two strands forming a double helix.

20
Q

Name the structure within which DNA is contained.

A

Chromosomes.

21
Q

What is a gene?

A

A small section of DNA on a chromosome.

22
Q

What is the function of a gene?

A

To code for a particular sequence of amino acids in order to make a specific protein.

23
Q

What is a genome?

A

The entire genetic material of an organism.

24
Q

State 3 ways in which understanding of the human genome will be important.

A
  1. To search for genes linked to different types of disease
  2. To understand and treat inherited disorders
  3. To trace early human migration patterns
25
Q

What is a chromosome?

A

A thread-like structure which contains coiled up DNA and proteins.

26
Q

What is an allele?

A

A different version of a gene.

27
Q

What does the term ?dominant? mean?

A

The individual only needs one copy of this allele for its phenotype to be seen.

28
Q

What does the term ?recessive? mean?

A

The individual needs two copies of this allele for its phenotype to be seen.

29
Q

What does the term ?homozygous? mean?

A

The individual has two identical alleles for this gene.

30
Q

What does the term ?heterozygous? mean?

A

The individual has two different alleles for this gene.

31
Q

What is a genotype?

A

The genetic makeup of an organism for a particular gene (e.g. RR).

32
Q

What is a phenotype?

A

The displayed characteristic due to the interactions between alleles (e.g. red flowers).

33
Q

How many pairs of chromosomes does an ordinary human body cell have?

A

23

34
Q

How many pairs of chromosomes determine the sex of the individual?

A

1

35
Q

What is the genotype of a female?

A

XX

36
Q

What is the genotype of a male?

A

XY

37
Q

What is polydactyly?

A

A condition that causes the individual to have extra fingers or toes.

38
Q

Is polydactyly a dominant or recessive condition?

A

Dominant.

39
Q

State the genotype(s) that would result in polydactyly.

A

PP or Pp (homozygous dominant or heterozygous for this gene).

40
Q

What is cystic fibrosis?

A

A condition which causes sticky mucus to build up in the lungs.

41
Q

Is cystic fibrosis a dominant or recessive condition?

A

Recessive.

42
Q

State the genotype(s) that would result in cystic fibrosis.

A

cc (homozygous recessive).

43
Q

State one method of screening embryos.

A

Amniocentesis/Chorionic villus sampling/IVF

44
Q

State one concern of screening embryos.

A

Causing miscarriage/Ethical concerns/Inaccurate results/Expensive

45
Q

State one benefit of embryo screening.

A

Know if child will have disorder/Able to decide if proceed with pregnancy or abortion