Inheritance

Question 1

Define a chromosome

Answer 1

Made of DNA and contains genetic information in the form of genes.

Question 2

Define a Gene

Answer 2

A length of DNA which codes for a protein.

Question 3

Define an allele

Answer 3

It is an alternative form of a gene

Question 4

Explain the sequence basis in a gene

Answer 4

The sequence bases in a gene determine the sequence of amino acids used to make a specific protein.

Question 4

Explain different sequences of amino acids

Answer 4

Different sequences of amino acids give different shapes to protein molecules.

Question 5

Explain DNA

Answer 5

DNA controls the cell function by controlling the production of proteins including enzymes , receptors for neurotransmitters and membrane carriers.

Question 6

What does DNA contain

Answer 6

2 long strands
4 nucleotides
Bases: AT CG

Question 7

What bases does mRNA

Answer 7

AU & CG

Question 8

Where does protein synthesis happen

Answer 8

Protein synthesis occurs outside the nucleus in the cytoplasm

Question 9

What 2 processes does protein synthesis go through

Answer 9

• Transcription (rewriting of bases of DNA for bases for RNA)
• Translation (

Question 10

How are proteins made

Answer 10

• the gene coding for the protein is made in the nucleus
• the messages RNA is a copy of a gene
• the mRNA is made in the nucleus and moves out into the cytoplasm
• the mRNA molecules pass through the ribosomes
• the ribosomes assemble the amino acids into protein molecules
• the specific sequence of bases of amino acids are determined y the sequence of bases in the mRNA.

Question 11

Explain most body cells

Answer 11

Most body cells contain the same genes but many genes in a particular cell are not expressed because the cell only makes specific proteins it needs.

Question 12

Explain haploid nucleus + examples

Answer 12

A nucleus containing a single set of chromosomes
- e.g sperm , egg

Question 13

Explain diploid nucleus

Answer 13

A nucleus containing two sets of chromosomes.
- e.g. body cells

Question 14

In a ______ cell there is a ____ of each type of chromosomes and in a human _______ cell there are ___ pairs.

Answer 14

Diploid
Pair
Diploid
23

Question 15

Explain mitosis

Answer 15

Mitosis is the nucleus division giving a rise to genetically identical cells.

Question 16

Role of mitosis

Answer 16

Growth - in animals , each tissue provides new cells when needed.

Replacement of cells -e.g. when you have a cut and new cells are generated to cover the wound.

Repair of damaged cells - of worn cells

Asexual reproduction- in plants

Question 17

When does replication occur in mitosis

Answer 17

The exact replication of chromosomes occurs before mitosis.

Question 18

What happens during mitosis

Answer 18

The copies of chromosomes separate maintaining the number of chromosomes in each daughter cell.

Question 19

Describe stem cells

Answer 19

Stem cells are unspecialized cells that divide through mitosis and produce daughter cells that become specialized for a specific function.

Question 20

What process is meiosis involved in

Answer 20

It is involved in the production of gametes.

Question 21

What is inheritance?

Answer 21

Inheritance is the genetic transmission from generation to generation

Question 22

What is meiosis

Answer 22

Meiosis is a reduction in the chromosome number where it is halved from diploid to haploid producing genetically different cells.

Question 23

Describe genotype

Answer 23

The genetic makeup in an organism and in terms of the alleles present

Question 24

Describe a phenotype

Answer 24

The observable features of an organism.

Question 25

Describe a dominant allele and what it looks like

Answer 25

An allele that is expressed if it is present in the genotype Capital letters

Question 26

Describe a recessive allele

Answer 26

An allele only expressed if there is dominant allele present of a particular gene , present in the genotype.

Question 27

How do you identify an unknown genotype

Answer 27

Test crosses

Question 28

What is the layout of a punnet square

Answer 28

Parents phenotype Parents genotypes Parents gametes (circle around each gamete ) Offspring genotypes (the square) Ratios

Question 29

What is a punnet square used for.

Answer 29

As a result of more than one genotypes is present to work out and show possible genotypes

Question 30

Describe co-dominance

Answer 30

A situation where bit alleles are expressed and play a part in the phenotype of a heterozygous and both of these alleles are dominant.

Question 31

Describe the blood group of AB

Answer 31

IA IB both dominant alleles giving one blood group AB.

Question 32

What is a sex-linked gene characteristics

Answer 32

A feature where the responsible gene is present in the sex chromosome that will make it more common in one sex than the other.

Question 33

What type of sex-linked recessive disorders.

Answer 33

X-linked recessive disorders are more prone in men. E.g. they have color blindness also the y- allele is shorter than the x/

Question 34

What is used to predict results of mono-hybrid crosses, co-dominance, sex-linkage and calculate phenotypic ratios.

Answer 34

A genetic diagram.