Inheritance

Question 1

Which of these statements is true
Genes make up chromosomes.
Chromosomes make up genes.

Answer 1

Genes make up chromosomes

Question 2

Different genes control the development of different _______________

Answer 2

Characteristics

Question 3

What is a gene

Answer 3

A section of DNA which codes for 1 characteristic

Question 4

Describe the structure of a DNA molecule

Answer 4

Double helix

Question 5

How can you work out the sequence if the bases on one strand by looking at the sequence on the other

Answer 5

It is always the opposite

Question 6

‘A’ goes with ___

And ‘C’ goes with ___

Answer 6

A –> T

C –> G

Question 7

___ bases code for one amino acid

Answer 7

3

Question 8

What is a mutation

Answer 8

A random change in the DNA

Question 9

What is the genotype

Answer 9

Your complete genetic identity… the allele pair (You may be {B b} or {B B}

Question 10

What is the phenotype

Answer 10

The observable characteristics (Brown eyes)

Question 11

Inside every cell in our bodies there is ___________ information. The information is carried in __________

Answer 11

Genetic information

Genes

Question 12

Some characteristics are not present due to genes but by the ______________

Answer 12

Environment

Question 13

Some genes can be controlled by both genes and the environment e.g…

Answer 13

For example height and weight

Question 14

List 2 examples of continuous variation in humans

Answer 14

Height

Weight

Question 15

List 3 types of discontinuous variation in humans

Answer 15

Eye colour
Hair colour
Blood type

Question 16

List 3 causes of variation

Answer 16

Genes
Environment
Mutation

Question 17

What are the 4 stages in mitosis in order

Answer 17

Prophase
Metaphase
Anaphase
Telophase

Question 18

Describe the main stages in the division of cell?

Answer 18

The dividing cell copies each chromosome before it divides. Therefore every cell has one copy of every chromosome. 2 chromatids make up each chromosome. These attach to a structure called a spindle. The spindles then shorten and pull the chromatids of each chromosome to the polar ends. 2 new nuclei form, both with a copy of each chromosome

Question 19

Why does the chromosome need to make an EXACT copy of itself before the cell can divide

Answer 19

Otherwise both cells will not receive all the genes

Question 20

When a cell is about to divide, it first makes an exact copy of each DNA molecule - this is called ______________

Answer 20

Replication

Question 21

How does a mutation occur

Answer 21

During replication, if a mistake is made.

Question 22

Name the 4 ways a mutation can occur

Answer 22

Duplication
Deletion
Substitution
Inversion

Question 23

Some _____________ occur in body cells and will only affect that particular cell. If the ___________ is not lethal and the cell containing the mutation divides, then a group of cells will have that ___________. When the organism dies, the ___________ is ______. Only a __________ in the __________ can be passed on to the next generation

Answer 23

Mutations
Mutation
Mutation
Mutation
Lost
Mutation
Gametes

Question 24

What are the 4 effects of mutations

Answer 24

Lethal
Harmful
Silent
Beneficial

Question 25

New alleles originate by __________

Answer 25

Mutation

Question 26

Only mutations in ________ can be inherited

Answer 26

Gametes

Question 27

New alleles introduce genetic ____________

Answer 27

Variation

Question 28

Causes of gene mutation

Answer 28

``` Ionising radiation Viruses and microorganisms Environmental poisons Tobacco Alcohol and diet ```

Question 29

What is an allele

Answer 29

A different version of a gene

Question 30

What does homozygous mean

Answer 30

The same alleles

Question 31

What does heterozygous mean

Answer 31

Different alleles

Question 32

Is it possible for a recessive allele to be passed on

Answer 32

Yes... both alleles must be present for that characteritic to be shown

Question 33

What is codominance

Answer 33

When the characteristics are mixed. The genotype is heterozygous. Neither allele is dominant or recessive to the other one. You get a mix of the 2 characteristics.

Question 34

Male genotype

Answer 34

XY

Question 35

Female genotype

Answer 35

XX

Question 36

DNA replication. The DNA must first ___________. An ___________ called helicase helps. Each strand acts a template. The DNA ________________ match up to the bases on each strand. C matches with ____ and A matches with ___. Another enzyme, DNA polymerase, joins the ________________ together along the new strand. Another enzyme, ligase, helps stick them together

Answer 36

``` Unwind Enzyme Nucleotides G T Nucleotides ```

Question 37

Chromosomes are located in a __________ which is surrounded by ______________

Answer 37

Nucleus | Cytoplasm

Question 38

Each ___________ consists of a row of genes

Answer 38

Chromosome

Question 39

Differences between organisms of the same species are known as ______________

Answer 39

Variation

Question 40

Body cells contain 46 chromosomes. Gametes contain half this number and are therefore said to be ___________

Answer 40

Haploid

Question 41

Number of chromsomes: Ovum

Answer 41

23

Question 42

Number of chromsomes: Sperm

Answer 42

23

Question 43

Number of chromsomes: Zygote

Answer 43

46

Question 44

Explain how mitosis results in cells with identical sets of genetic information

Answer 44

Because before the cells divide the DNA replicates itself. The chromosome then splits in 2 before the cell splits sp both cells have an identicle chromosome

Question 45

First the DNA ___________ Then, the DNA copies itself before it coils up and forms _______________ The _______________ then line up in the centre of the cell Next, the arms of each ________________ are pulled apart New _____________ form around the cell nuclei The cell divides. This process is known as ___________.

Answer 45

``` Uncoils Chromosomes Chromosomes Chromosome Membranes Mitosis ```

Question 46

Why do gametes have half the usual number of chromosomes

Answer 46

For variation, when fertilisation occurs it goes back to the usual number

Question 47

How does gamete formation lead to genetic variation

Answer 47

The child isn't identical to one parent. It's a mix of both.

Question 48

New forms of genes arise from changes known as ___________________ in the existing genes. These occur naturally and are important for producing ______________

Answer 48

Mutations | Variation

Question 49

Name something which increases the chance of a mutation occuring

Answer 49

Exposure to ionising radiation | Exposure to chemicals known as mutagenes

Question 50

What has to happen for a mutation to be passed on

Answer 50

The mutation has to occur in the sex cells