B13: Reproduction

Question 1

What does meiosis lead to?

Answer 1

Non-identical cells

Question 2

What are the male and female gametes in plants?

Answer 2

Pollen and egg cells

Question 3

What happens in sexual reproduction? What type of cell division is used here?

Answer 3

A mix in genetic information which leads to variety in the offspring. The formation of gametes involves meiosis

Question 4

What happens in asexual reproduction? What type of cell division is used here?

Answer 4

No fusion of gametes due to one parent present. No mixing of genetic information, leading to identical offspring due to mitosis

Question 5

What are the 3 key stages is meiosis?

Answer 5

Copies of genetic material are made, the cell divides twice to form 4 gametes, each with a single set of chromosomes and all gametes are genetically different from each other

Question 6

What are 3 advantages of sexual reproduction?

Answer 6

Produces variation in the offspring, variation gives a survival advantage by natural selection and this can be speeded up by humans in selective breeding to increase food production

Question 7

What are 3 advantages of asexual reproduction?

Answer 7

Only one parent needed, faster than reproduction and many identical offspring when conditions are favourable

Question 8

List 3 organisms that reproduce both sexually and asexually

Answer 8

Malarial parasites, fungi and some plants like daffodils and strawberry plants

Question 9

How do malarial parasites reproduce?

Answer 9

Asexually in human host, but sexually in mosquito

Question 10

How do fungi reproduce?

Answer 10

Asexually by spores, but sexually to give variation

Question 11

How do some plants reproduce?

Answer 11

Asexually by runners for strawberry plants, or bulb division for daffodils, but also sexually to produce seeds

Question 12

Where is DNA contained

Answer 12

In the chromosomes, which are in the nucleus of a cell

Question 13

What is a gene?

Answer 13

A small section of DNA on a chromosome

Question 14

Why are genes useful?

Answer 14

They code for a particular sequence of amino acids, to make a specific protein

Question 15

Give 3 reasons why understanding the human genome is important?

Answer 15

There can be searches for genes linked to different types of disease, an understanding and treatment of inherited disorders and can be used in tracing human migration patterns

Question 16

What is the code for an amino acid?

Answer 16

A sequence of 3 bases

Question 17

Where are proteins synthesised?

Answer 17

On ribosomes

Question 18

What is the function of carrier molecules?

Answer 18

They bring specific amino acids to add to the growing protein chain in the correct order

Question 19

What are 3 uses of proteins in the body?

Answer 19

Enzymes, hormones and forming structures

Question 20

What is the function of non-coding parts?

Answer 20

They can switch genes on and off, so variations in these areas of DNA may affect how genes are expressed.

Question 21

What causes Polydactyly?

Answer 21

A dominant allele

Question 22

What causes Cystic Fibrosis?

Answer 22

A recessive allele

Question 23

Why is sexual reproduction being a quick process an advantage?

Answer 23

Because it can colonise a new area quickly

Question 24

What are 2 disadvantages of asexual reproduction?

Answer 24

No genetic variation, meaning that a whole population could be wiped out due to disease and less chance of adapting to new conditions

Question 25

What is a disadvantage of sexual reproduction?

Answer 25

Takes more time and energy

Question 26

What is an allele?

Answer 26

A different version of the same gene

Question 27

What is a genotype?

Answer 27

A collection of all the alleles we have

Question 28

What is a phenotype?

Answer 28

The characteristic you get from the genotype, e.g. green eyes

Question 29

What are differences between mRNA and DNA?

Answer 29

Much shorter, contains uracil instead of thymine and only a single strand

Question 30

Why does DNA have to be copied to mRNA?

Answer 30

Because it is too big to leave the nucleus

Question 31

What increases the risk of a mutation?

Answer 31

Carcinogens and radioactive substances

Question 32

What are the 3 types of mutations?

Answer 32

Substitutions, insertions and deletions

Question 33

Where do most mutations occur?

Answer 33

In non-coding regions

Question 34

What is embryo screening?

Answer 34

The process of checking if an embryo has any genetic disorders, and these embryos can be discarded

Question 35

What are advantages of embryonic screening?

Answer 35

Saves money and reduces suffering as less people will have a disorder

Question 36

What are disadvantages of embryonic screening?

Answer 36

Implies that people with genetic disorders are undesirable, and people could be screening for other traits in the future

Question 37

What is cystic fibrosis?

Answer 37

When cell membranes are covered with sticky mucus