Genetics

Question 1

What is fertilisation?

Answer 1

Fusion of male and female gametes

Question 2

What are examples of gametes?

Answer 2

Egg cell, sperm cell, pollen and eggs

Question 3

How many chromosomes does a human gamete have?

Answer 3

23

Question 4

What is sexual reproduction?

Answer 4

The fusion of male and female gametes

It does not have to include sex

Question 5

What is asexual reproduction?

Answer 5

• Only one parent
• No mixing of genetic material (no genetic variation)
• All off spring are identical clones

Question 6

How is asexual reproduction achieved in eukaryotic organisms?

Answer 6

Through mitosis

Question 7

How is asexual reproduction achieved is prokaryotic organisms?

Answer 7

Through binary fission

Question 8

What are haploid cells?

Answer 8

They have half the genetic material of a normal cell

Question 9

What are diploid cells?

Answer 9

Has two sets of genetic information (one from each parent)

Question 10

What are maternal chromosomes?

Answer 10

The chromosomes from the mother

Question 11

What are paternal chromosomes?

Answer 11

The chromosomes from the father

Question 12

How many chromosomes are in one cell?

Answer 12

46

Question 13

What are the steps of meisis?

Answer 13

1) Replicate DNA
2) Chromosomes line up in the centre of the cell
3) Chromosome pairs are pulled apart (chromosomes randomly distributed)
4) Cell divides in half
5) Chromosomes all line up at the centre of the cell
6) Arms of the chromosomes are pulled to each side of the cells
7) The chromosomes then both divide in half again (there are now 4 genetically unique cells)

Question 14

During meiosis, how many times does the cell divide?

Answer 14

2 times

Question 15

During meiosis, how many cells are produced?

Answer 15

4 cells

Question 16

How would you describe DNA?

Answer 16

2 strands wrapped around in a double helix

Question 17

How long is DNA if you rolled it all out?

Answer 17

2m

Question 18

How many sections is DNA sectioned into?

Answer 18

46 sections (tight coil called chromosomes)

Question 19

What types of chromosomes do women have?

Answer 19

2 X chromosomes (XX)

Question 20

What types of chromosomes do men have?

Answer 20

XY Chromosomes

Question 21

What is a gene?

Answer 21

A small section of DNA that codes for a protein (small segment of a chromosome and code for amino acids)

Question 22

What is a genome?

Answer 22

Entire set of genetic material in an organism

Question 23

What are alleles?

Answer 23

Different versions of the same gene

Question 24

What does homozygous mean?

Answer 24

2 alleles that are the same

Question 25

What does heterozygous mean?

Answer 25

2 alleles that are different

Question 26

What is a dominant allele?

Answer 26

The dominant allele always gets expressed (e.g. dominant brown hair, will always be brown)

Question 27

What is a recessive allele?

Answer 27

An allele that needs two recessive alleles to be expressed (both parents need to have blonde hair for the offspring to have blonde hair)

Question 28

What does genotype mean?

Answer 28

- The entire section of alleles that we have or - The two alleles present for a particular gene

Question 29

What does phenotype?

Answer 29

The characteristics we get from our genotype

Question 30

Where are chromosomes found in the cell?

Answer 30

The nucleus

Question 31

What are each monomer of DNA called?

Answer 31

A nucleotide

Question 32

What are nucleotides made up of?

Answer 32

- Phosphate - Sugar - Base

Question 33

What are the 4 different types of bases in a nucleotide?

Answer 33

- Adenine - Thymine - Cytosine - Guanine

Question 34

What is a sugar phosphate backbone?

Answer 34

The long chain of where the phosphate bonds to the sugar on each nucleotide

Question 35

What are the complementary bases that always have to pair up with each other?

Answer 35

Adenine and Thymine | Cytosine and Guanine

Question 36

What is a genetic code?

Answer 36

The sequence of bases

Question 37

What are each group of three bases called?

Answer 37

A triplet (codes for specific amino acids)

Question 38

What are the steps for forming a protein?

Answer 38

- Cells will read the DNA base sequence in a series of triplet codes - Take the amino acids and each triplet codes form and combine them all to be in that same order - Then the long chain of amino acids will fold up and form a protein

Question 39

What are the main uses of protein?

Answer 39

- Enzymes - Hormones - Structural proteins

Question 40

Is cystic fibrosis, a dominant or recessive gene?

Answer 40

Recessive

Question 41

What is an inherited disorder?

Answer 41

Group of conditions that can be passed on in alleles

Question 42

What is polydactyly?

Answer 42

- A baby is born with extra fingers or toes - It doesn't usually cause any other problems - Caused by a dominated allele

Question 43

What is cystic fibrosis?

Answer 43

A disorder of the membranes | Results in thick sticky mucus

Question 44

What is embryonic screening?

Answer 44

Looking at the embryo's genes, to see if it's carrying any diseases

Question 45

What the advantages for embryonic screening?

Answer 45

- Help reduce overall amount of suffering | - Save money

Question 46

What are the disadvantages for embryonic screening?

Answer 46

- Implies that people with genetic problems are undesirable | - Future screening for other traits

Question 47

What does variation mean?

Answer 47

Individuals that are all different and have different phenotypes

Question 48

What are more of our characteristics determined by?

Answer 48

The interactions of our genes and our environment

Question 49

Why are there so many genetic variations?

Answer 49

Because of mutations

Question 50

What is a mutation?

Answer 50

A change in the DNA code - protein coded for may be different Most mutations don't have any effect on proteins

Question 51

What happens in the mutation does have an effect on the protein?

Answer 51

- Mutations are usually something bad | - Occasionally beneficial

Question 52

What does the term 'survival of the fittest' mean?

Answer 52

Beneficial mutations mean that they're more likely to survive and pass down their mutation

Question 53

What is natural selection?

Answer 53

Fittest individuals selected to survive

Question 54

What is evolution?

Answer 54

Inheritance of certain characteristics in a population, over multiple generations, can lead to changes in the whole species - or development of an entirely new species

Question 55

What does continuous variation mean?

Answer 55

Where the characteristics changes gradually over a range of values such as, height, body mass, or skin colour. This is usually influenced by genes

Question 56

What does discontinuous variation mean?

Answer 56

Where the characteristic has distinct forms, with no overlap. For example, eye colour is discontinuous. Usually influenced by one or two genes

Question 57

What is speciation?

Answer 57

The evolutionary process by which populations evolve to become distinct species.