7-Cell Division+Inheritance Flashcards Preview

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Flashcards in 7-Cell Division+Inheritance Deck (37)
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0
Q

What are chromosomes made up of?

A

Large molecules of DNA which has a double helix structure.

1
Q

Where are chromosomes found?

A

In the nucleus of cells.

2
Q

What is a gene?

A

A section of DNA.

3
Q

How many chromosomes are there in a body cell?

A

46 or 23 pairs.

4
Q

How many chromosomes in a gamete?

A

23.

5
Q

What does the fusion of gametes produce?

A

A zygote which has 46 chromosomes.

6
Q

How many of the pairs of chromosomes in the human body are sex chromosomes?

A

1.

7
Q

What is the female chromosome called?

A

X chromosomes.

8
Q

What is the male chromosome called?

A

Y chromosome.

9
Q

What is the sex of a child decided by?

A

The sperm. If it’s X-carrying or Y-carrying (X=girl,Y=boy).

10
Q

What is mitosis?

A

The division of body cells to produce new cells.

11
Q

What is mitosis used for?

A

Growth and repair, and asexual reproduction.

12
Q

What happens to the chromosomes in mitosis?

A

They make a copy so each cell has the same genetic information as the parent.

13
Q

What is the order of what happens in mitosis?

A
  1. Parent cell with 2 pairs of chromosomes.
  2. Each chromosome replicates itself.
  3. Copies pulled apart as cell divides.
  4. Two ‘daughter’ cells with same genetic information.
14
Q

Where does meiosis occur?

A

In the testes and ovaries.

15
Q

What is the order of what happens in meiosis?

A
  1. Cell with two pairs of chromosomes.
  2. Each chromosome replicates itself.
  3. Copies pulled apart and cell divides.
  4. Copies separate again as cell divides a second time.
  5. Four gametes formed each with half the number of chromosomes of parent cell.
16
Q

What happens during fertilisation?

A

One chromosome comes from each parent and a single body cell with new pairs of chromosomes are formed. This cell divides repeatedly to form a new individual.

17
Q

What are alleles?

A

Different forms of genes.

18
Q

What are the two types of alleles?

A

Dominant or recessive.

19
Q

What will happen if the are two dominant alleles?

A

The dominant allele will control the characteristic.

20
Q

What happens if there is a dominant and a recessive allele?

A

The dominant allele will control the characteristic.

21
Q

What happens if there are two recessive alleles?

A

The recessive allele will control the characteristic.

22
Q

What is monohybrid inheritance?

A

When a characteristic is controlled by only one pair of alleles. You can do genetic crosses to see how people will inherit.

23
Q

What is homozygous?

A

An individual with two of the same alleles.

24
Q

What is heterozygous?

A

An individual with two different alleles.

25
Q

What is the phenotype?

A

The characteristic that ‘shows’ itself. Eg. Brown eyes.

26
Q

What is the genotype?

A

The alleles present. Eg. One brown-eye allele and one blue-eye allele.

27
Q

What is differentiation?

A

When cells develop a specialised structure to carry out a specific function.

28
Q

How do animal cells and plant cells differentiate?

A

Animal cells-At an early stage so quickly become muscle, nerves, etc.
Plant cells-Differentiate throughout life.

29
Q

What are stem cells?

A

Cells that have yet to differentiate.

30
Q

Where can human stem cells be found?

A

In human embryos and adult bone marrow.

31
Q

What is DNA?

A

Deoxyribonucleic acid.

32
Q

How do genes code for a particular characteristic?

A

By providing a code for a combination of amino acids, which make up a protein. Different combinations make different proteins.

33
Q

What is polydactyly and what type of allele causes it?

A

It is having extra finger or toes and is caused by a dominant allele.

34
Q

What is cystic fibrosis and what type of allele causes it?

A

It is a disorder of cell membranes and is caused by a recessive allele.

35
Q

Name some pros and cons of stem cell research.

A

Pros:
*embryos only a few days old, many see them as only microscopic balls of cells
*embryos provide most useful stem cells as adult ones are more limited
*can act as repair kit fir damaged tissue
*could treat many diseases/conditions in the future
Cons:
*many believe it morally wrong
*embryos cultured using nutrients from animal sources, could carry diseases that could be passed to humans
*people who receive cell transplants from stem cell therapy could be infected with viruses
*stem cells may turn cancerous

36
Q

Name some pros and cons of embryo screening.

A

Pros:
*doctors can see if a child will have increased risk of getting an illness/disease
*prepares parents for possibility of a child developing a disorder, disease or illness
*carriers of genetic disorders can decide wether or not to have children
Cons:
*could result in abortions if genetic makeup ‘faulty’
*parents may want to choose genetic makeup of child
*potential to be used to decide who can/cannot have children
*could upset people to learn they carry a genetic disorder, disease or illness