B13 - Reproduction Flashcards Preview

AQA GCSE Biology > B13 - Reproduction > Flashcards

Flashcards in B13 - Reproduction Deck (27)
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1
Q

D. Asexual reproduction

A

Involves one parent which produces a genetically identical clone by mitosis as there is no fusion of gametes.

2
Q

D. Sexual reproduction

A

Involves the fusion of male and female gametes formed by meiosis

3
Q

How many chromosomes does the zygote have?

A

46

4
Q

Variation caused by?

A

In sexual reproduction there is a mixing of genetic information which leads to variation

5
Q

D. Mitosis

A

Making identical two

6
Q

D. Meiosis

A

Making eggs and sperm

7
Q

Meiosis results in?

A

Sex cells called gametes which have half the original no. of chromosomes

8
Q

Where are:
Female gametes made?
Male gametes made?

A

f- ovaries

m- testes

9
Q

D. Haploid?

A

Half the usual number of chromosomes

10
Q

D. Genome?

A

Entire genetic material of an organism

11
Q

DNA is a …….

A

polymer

12
Q

D. Gene?

A

Small section of DNA on a chromosome

13
Q

D. Homozygote?

A

an individual with 2 identical alleles for a characteristic

14
Q

D. Hetrozygote?

A

an individual with 2 different alleles for a characteristic

15
Q

D. Genotype?

A

Alleles present or the genetic makeup of an individual, regarding a particular characteristic (eg. Bb or bb)

16
Q

D. Phenotype?

A

describes the physical appearance of an individual regarding a particular characteristic (eg. black fur)

17
Q

D. Dominant allele?

A

expressed in the phenotype, even if only one copy is present

18
Q

Female sex chromosomes?

A

the same - XX

19
Q

Male sex chromosomes?

A

Different - XY

20
Q

Polydactyly?

A

Babies born with extra fingers or toes

21
Q

What type of allele is polydactyly caused by?

A

dominant

22
Q

What type of allele is cystic fibrosis caused by?

A

recessive

23
Q

How does cystic fibrosis affect body?

A
  • affects cell membranes - prevents movement of substances
  • mucus becomes thick, so organs like lungs become clogged up
  • pancreas cannot secrete enzymes properly because tubes blocked, so stunted growth
24
Q

When is amniocentesis carried out?

A

15-16 weeks of pregnancy

25
Q

Ways to test embryos for genetic diseases?

A
  • amniocentesis

- chorionic villus sampling

26
Q

How does chorionic villus sampling work?

A

small sample of placenta is taken at around 10-12 weeks to provide fetal cells to screen

27
Q

How does amniocentesis work?

A

takes a sample of fluid from around fetus which contains fetal cells that can be screened