Inheritance

Question 1

Genome

Answer 1

All the DNA of an organism

Question 2

Gene

Answer 2

A section of DNA that codes for a specific protein

Question 3

Alleles

Answer 3

A version of a gene which codes for different proteins

Question 4

Dominent Allele

Answer 4

When one allele is present in genotype it is always expressed in phenotype

Question 5

Recessive Allele

Answer 5

Needs both alleles to be present in genotype to be expressed in phenotype

Question 6

Homozygous

Answer 6

Both chromosomes have the same allele

Question 7

Heterezygous

Answer 7

Contains one of each allele

Question 8

Phenotype

Answer 8

Visual characteristics

Question 9

Genotype

Answer 9

Combination of alleles

Question 10

Polygenic Inheritence

Answer 10

• Characteristic is controlled by two or more genes
• Wide range of variation - lots of combinations
• E.g height, skin colour, eye colour

Question 11

Monohybrid inheritence

Answer 11

• single gene with two alleles
• gene passed from parents

Question 12

Mitosis

Answer 12

Cell divides producing two genetically identical daughter cells

Question 14

Mitosis occurs during…

Answer 14

• Growth
• Repair
• Cloning/Replacing
• Aexual Reproduction

Question 16

Mitosis process

Answer 16

1. Interphase – DNA is replicated
2. Prophase – Chromosomes visible; spindle fibres form and nuclear membrane breaksdown
3. Metaphase – Chromosomes line up along the cell equator, attached to spindle fibres
4. Anaphase – Spindle fibres contract, pulling sister chromatids apart to opposite poles
5. Telophase – New nucleur membranes, cytoplasm divides - two daughter cells

Question 17

Process of Meisosis

Answer 17

• Parent cell grows
• DNA replicates – chromosomes are copied
• Homologous chromosomes pair up
• Chromosomes exchange sections of DNA
• Homologous chromosomes are pulled apart
• Cell divides – two cells formed
• In each new cell, sister chromatids separate
• Cells divide again, forming four genetically different haploid cells

Question 18

Human Diploid Number

Answer 18

46 chromosomes

Question 19

Human Haploid Number

Answer 19

23 Chromosome pairs

Question 20

Mitosis Characteristics

Answer 20

• Asexual reproduction
• growth and repair
• two identical daughter cells
• one cell division
• occurs throughout human body/plant

Question 21

Meiosis Characteristics

Answer 21

• Sexual reproduction
• produces gametes
• genetic variation in four daughter cells
• two cell divisions
• occurs in ovary and testis/ovary and anther

Question 22

Genetic Variation

Answer 22

Following sexual reproduction or mutations organisms will have different versions of genes to an individual

Question 23

Enviromental Variation

Answer 23

enviroment affects the characteristics of an organism

Question 24

Mutation

Answer 24

A change in the seqeunce of bases in the DNA of a cell

Question 25

Mutations are...

Answer 25

rare and random changes in genetic material that can be inherited

Question 26

Charles Darwins two observations

Answer 26

1. Living things tend to over-reproduce 2. All living things/organisms show variation

Question 27

What did Charles Darwin deduce from his observations

Answer 27

1. There is a struggle for existence as there is competition for resources 2. Organisms bst suited to their enviroment would survive and reproduce

Question 28

Natural Selection Method

Answer 28

1. Variation occurs due to random mutations 2. Changing conditions in the enviroment favours some of the species 3. These individuals are more likely to survive and reproduce - better sutied to enviroment 4. They will pass on their advantageous alleles to there offspring 5. Offspring will inherit favoured characterestics 6. Advantageous allele is passed down generations 7. Less favourable alleles tend to become less common

Question 29

Antibiotics

Answer 29

Chemicals that kill bacteria and do not usually harb animals

Question 30

Antibiotic Resistance in bacteria occurs...

Answer 30

because natural selection happens in response to overuse of antibiotics

Question 31

Antibiotic resistance in bacteria

Answer 31

1. Random mutations gave some bacteria resistance to antibiotics 2. These bacteria were better adapted to the enviroment - advantageous mutant allele to survive 3. Reproduce and pass on the resistance allele and those bacteria without advantageous mutant allele die. 4. This repeated with each generation of bacteria 5. Proportion of bacteria with the resistance allele increased until most had allele

Question 32

Why is bacteria resistance so bad?

Answer 32

New antibiotics have to be created to treat the resistance bacteria population

Question 33

Doctors are less likely to use Antibiotics:

Answer 33

- Reduces number of bacteria with resistence having selective advantage - so reduces chance of survival and reproduction - prevents them passing mutated allele to offspring