3B Inheritance

Question 1

What is the genome?

Answer 1

All of the genes present in an organism

Question 2

What is a gamete?

Answer 2

Gametes are sex cells (sperm or eggs)

Question 3

What is a chromosome?

Answer 3

Tightly packaged DNA

Question 4

How many chromosomes do human body cells have?

Answer 4

46 chromosomes (23 pairs)

Question 5

How many chromosomes do human gametes have?

Answer 5

23 chromosomes

Question 6

Where are chromosomes located?

Answer 6

In the nucleus of the cell

Question 7

What is a gene?

Answer 7

A section of DNA that codes for a protein

Question 8

What is an allele?

Answer 8

Different versions of the same gene

Question 9

What is a dominant allele?

Answer 9

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

Question 10

What is a recessive allele?

Answer 10

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

Question 11

What is meant when an organism is homozygous?

Answer 11

Has two copies of the same allele

Question 12

What is meant when an organism is heterozygous?

Answer 12

Has two different versions of the same gene (one dominant and one recessive)

Question 13

What is the genotype?

Answer 13

The genes present for a trait
e.g Aa

Question 14

What is the phenotype?

Answer 14

The visible characteristic

Question 15

What is monohybrid inheritance?

Answer 15

The inheritance of one allele

Question 16

Things to include in punnet squares

Answer 16

• Alleles (and person that carries it)
• Ratio / Percentage

Question 17

What do family pedigrees show?

Answer 17

The inheritance of an allele over generations

Question 18

3 processes that require mitosis

Answer 18

• growth
• repair
• asexual reproduction

Question 19

How many cells does mitosis produce

Answer 19

One parent cell produces two daughter cells.

Question 20

How many cells does meiosis produce?

Answer 20

One parent cell produces 4 daughter cells

Question 21

2 differences between mitosis and meiosis

Answer 21

• Mitosis produces 2 genetically identical cells whereas meiosis produces 4
• Mitosis produces diploid cells whereas meiosis produces haploid cells

Question 22

What is random fertilisation?

Answer 22

• The random chance of fertilising a specific sperm with a specific egg
• This increases variation as any female can mate with any male and any one of the millions of sperm could fertilise the egg

Question 23

What are the two types of variation?

Answer 23

Genetic variation and environmetal variation

Question 24

2 traits in humans caused only by genetic variation

Answer 24

• Eye colour
• Blood type

Question 25

2 traits in humans caused by a mix of environmental and genetic variation

Answer 25

• Height
• Weight

Question 26

What is a mutation

Answer 26

A random change in the genetic material of an organism

Question 27

Natural selection

Answer 27

• There is variation in “specific characteristic”
• The mutation with “” provides a selective advantage in “ “
• The organism with the mutation “” survives
• reproduces and pass on the alleles

Question 28

Define evolution

Answer 28

Evolution is a change in the genetic makeup of a population over time due to natural selection

Question 29

Describe how anitbiotic resistance arises

Answer 29

• A random genetic mutation causes a bacterium to become resistant to the antibiotic
• When the antibiotic is used, all the bacteria that do not have the mutation are killed
• The population containing just the resistant bacteria mutation then begins to grow