Genetics

Question 1

2 types of variations of genes

Answer 1

Environmental
Genetic

Question 2

Different components of animal cell

Answer 2

Nucleus controls the cell and contains DNA/ Chromosomes
Cytoplasm - chemical reactions
Cell membrane - allows things to leave/enters
Mitochondria - respiration

Question 3

Structure of DNA?

Answer 3

DNA is double stranded, double helix molecule.
Found in the nucleus
Provides our genetic code
It is made up of chromosomes

Question 4

How many pairs of chromosomes?

Answer 4

23 pairs (46 chromosomes)

Question 5

How many chromosomes are in sex cell ?

Answer 5

23 chromosomes

Question 6

Generic name for sex cells?

Answer 6

Gamete

Question 7

Unfertilised egg cell?

Answer 7

Ovum

Question 8

Fertilised egg cell ?

Answer 8

Zygote

Question 9

How is a genetic disorder inherited?

Answer 9

Half genes from each biological parent and may inherit a gene mutation from one parent or both.

Question 10

What is a gene?

Answer 10

Coding part of chromosome e.g. eye colour

Question 11

What is an allele?

Answer 11

Pair of genes

Question 12

Person with two identical alleles ?

Answer 12

homozygous alleles e.g. TT

Question 13

Person with two different alleles ?

Answer 13

heterozygous alleles e.g. Tt

Question 14

Genotype?

Answer 14

Genetic make-up inherited from mum and dad e.g. Bb

Question 15

Phenotype?

Answer 15

Physical attributes e.g. blue eyes

Question 16

Punett square?

Answer 16

Work out cross between 2 people (genotype and phenotype)

Question 17

Cross-breeding or Selective Breeding?

Answer 17

1. Choose parents to breed
2. Breed these parents.
3. Choose the best offspring, to produce the next generation.
4. Repeat the process continuously until all offspring show the desired characteristics.

Cross-breed: produce offspring with traits from both parents e.g. normal human
Selective: select for desired characteristics

Question 18

Genetic Engeering?

Answer 18

Alters the DNA of an organism by inserting, removing, or modifying specific genes .

It creates organisms not normally possible

1. Select desired characteristic.
2. Cut gene out of chromosome (enzyme)
3. Transfer gene into another organism.
4. Produce new characteristic

Question 19

Advantages of cross-breeding

Answer 19

desired characteristic
avoid genetic defects
aesthetic reasons
Economic
Eliminate Disease
New varieties
Change evolution of a species
Fitter/stronger animals

Question 20

Disadvantages of inbreeding

Answer 20

susceptible to diseases
Reduces gene pool
genetic defects

Question 21

What are the stages of selective breeding?

Answer 21

1. Choose parents to breed
2. Breed these parents.
3. Choose the best offspring, to produce the next generation.
4. Repeat the process continuously over many generations, until all offspring show the desired characteristics.

Question 22

GMO?

Answer 22

Genetically Modified Organisms

Question 23

Advantages and disadvantages of genetically engineering organisms?

Answer 23

Advantages:
Cure for genetic disease e.g. insulin
Produce new foods
Getting rid of illness
More nutrients
Less pesticides
Improve diet
Resistant to disease
Produce greater yield

Disadvantages:
Expensive so available to select group
Unknown impact of GMO crops e.g. allergies
Harmful changes to animals

Question 24

What are the male and female genotypes?

Answer 24

XX and XY

Question 25

What process MODIFIES genes in an organism?

Answer 25

Genetic engineering

Question 26

What process produces organisms with identical genes e.g insulin?

Answer 26

Cloning

Question 27

What is a clone

Answer 27

Making a genetically identical copy of an individual (naturally e.g. twins or artificially)

Question 28

What causes a cell to be genetically identical

Answer 28

The cell copies - or 'replicates' - its chromosomes, and then splits the copied chromosomes equally

Question 29

What is cell division called?

Answer 29

Mitosis (Meiosis is specifically sex cells)

Question 30

Why does sexual reproduction produce a new variety of onion?

Answer 30

Combines genetic material from 2 parent onions Mixing of genes produces onions with different traits e.g. size, shape, flavour

Question 31

How do mitochondria help sperm cells carry out their function?

Answer 31

Produce energy for the movement of the sperm.

Question 32

Why is nucleus in sperm cell different to other body cells

Answer 32

Sperm cells only contain one set of chromosomes (23 !)

Question 33

Why stem cell used to treat some diseases?

Answer 33

Replace cells that are damaged Stem cells can divide to produce new cells, which can then divide into different cell types. They therefore have the potential to be transplanted into patients to treat disease.

Question 34

What is sexual reproduction?

Answer 34

Gamete (sperm cell) + gamete (ovum/egg cell) = zygote (fertilised egg cell)

Question 35

Asexual reproduction and advantage?

Answer 35

Reproduce by themselves, no fertilisation, no gametes, much quicker