Unit 2: 5 - Simple inheritance

Question 1

Why is cell division necessary?

Answer 1

For growth or cell repair.

Question 2

What is mitosis?

Answer 2

A division process resulting in 2 identical cells.

Question 3

What are alleles?

Answer 3

Each of 2 or more alternate genes for one characteristic.

Question 4

What happens to chromosomes during mitosis?

Answer 4

They duplicate, and the new copy goes in the newly formed cell.

Question 5

What are unspecialised cells?

Answer 5

Stem cells

Question 6

When does stem cell differentiation occur in animals?

Answer 6

During early stages of development (in humans, as an embryo)

Question 7

When does stem cell differentiation occur in plants?

Answer 7

Anytime throughout their lives.

Question 8

Cells of offspring are produced by _____ during asexual reproduction.

Answer 8

Mitosis

Question 9

Cells of offspring are produced by _____ during sexual reproduction.

Answer 9

Meiosis

Question 10

What is meiosis?

Answer 10

When cells divide to become gametes (sperm and ova in humans)

Question 11

What is the difference between gametes and normal cells?

Answer 11

Gametes have only one chromosome from each pair that normal cells have.

Question 12

Describe the processes of meiosis.

Answer 12

1. A copy of each chromosome is made.
2. The cell now divides twice to form 4 gametes
3. Each gamete has a single set of chromosomes with a different combination of genes.

Question 13

Where are stem cells found in a human?

Answer 13

In an embryo or in adult bone marrow.

Question 14

What cells do bone marrow stem cells become?

Answer 14

Often blood cells.

Question 15

What medical uses could stem cells have?

Answer 15

Regrowing nerve cells to treat conditions like paralysis.

Question 16

Who was the first person to suggest the idea of separately inherited ‘factors’?

Answer 16

Gregor Mendel.

Question 17

Why were Mendel’s ideas not accepted?

Answer 17

Because scientists didn’t know about genes and Mendel was not in an academic position; he was a monk.

Question 18

What are chromosomes made of?

Answer 18

DNA, a long double helix molecule.

Question 19

What does DNA stand for?

Answer 19

Deoxyribonucleic Acid

Question 20

What is a DNA fingerprint?

Answer 20

A unique DNA structure (apart from in identical twins) can be used to identify any individual.

Question 21

How many pairs of chromosomes do human beings have?

Answer 21

23

Question 22

What do we call an allele that is shown in the characteristics of an organism? (If there is only 1)

Answer 22

A dominant allele

Question 23

What do we call an allele that is ‘hidden’ and is not made evident? (If there is only 1)

Answer 23

A recessive allele

Question 24

What does homozygous mean?

Answer 24

When both alleles are the same (DD)

Question 25

What does heterozygous mean?

Answer 25

When both alleles are different (Dd)

Question 26

What is the phenotype?

Answer 26

The physical appearance of the charatceristic (e.g. dimples or no dimples)

Question 27

What is the genotype?

Answer 27

The genetic make up - which alleles does the individual inherit? DD, Dd or dd.

Question 28

What is a genetic disorder?

Answer 28

A disorder that is carried in the genes and passed down through generations.

Question 29

What is polydactyly?

Answer 29

A genetic disorder where a baby is born with extra fingers or toes.

Question 30

What type of allele is polydactyly?

Answer 30

Dominant

Question 31

How many parents are needed to pass down a dominant allele?

Answer 31

1

Question 32

What is cystic fibrosis?

Answer 32

A genetic disorder that affects the cell membranes and causes the production of a thick mucus that affects organs like the lungs and gut.

Question 33

What type of allele is cystic fibrosis?

Answer 33

Recessive

Question 34

How many parents are needed to create a child with a disorder which is recessive?

Answer 34

2

Question 35

How does a child develop cystic fibrosis?

Answer 35

By having a recessive allele from each parent

Question 36

What do we call someone who has a recessive gene for a disorder but does not have the disorder?

Answer 36

A carrier

Question 37

What is the chance of a parent who is heterozygous for polydactyly for passing it on to the child?

Answer 37

50%

Question 38

If both parents are heterozygous for cystic fibrosis, what is the chance of passing it on to the child?

Answer 38

25%

Question 39

How can we show the possible outcomes of genetic crosses?

Answer 39

Through a Punnet square

Question 40

What is the main ethical problem with embryo screening?

Answer 40

Many parents would want to choose a baby which does not have cystic fibrosis, which would discriminate over those who do,a swell as waste life.

Question 41

What is a problem with using embryonic stem cells?

Answer 41

The embryos are destroyed in the process.