Biology - B1

Question 1

What is an allele?

Answer 1

The different version of the same gene

Question 2

What are the structural proteins

Answer 2

Part of thing like skin, hair, blood and cytoplasm e.g. Collagen is a structural protein that is found in tendon, bones and cartilage

Question 3

What is functional proteins

Answer 3

E.g. Enzymes are proteins that helps with digestion by breaking down food molecules - AMYLASE is a digestive enzyme that breaks down starch to maltose

Question 4

What is a genotype

Answer 4

The gene it has

Question 5

What is a phenotype

Answer 5

The characters than an organism displays

Question 6

What are environmental factors?

Answer 6

Scars, weight, hair colour, broken bones

Question 7

What are genetic factors

Answer 7

Dimples, eye colour, skin colour, height and weight

Question 8

Sperm and egg cells have half the normal amount of DNA, why?

Answer 8

Sex cells are different from any other cells, contains 23 single chromosomes

Fertilisation= the 23 chromosomes from the egg and the 23 chromosomes from the speed combine

The fertilised egg then has 23 pairs of chromosomes

The two chromosomes in a pair always carry the same gene, but because the pair came from different parents they have different alleles.

Question 9

Homozygous

Answer 9

Two alleles the SAME

Question 10

Heterozygous

Answer 10

Two alleles that are DIFFERENT

Question 11

Why does one gene determine which sex organs you develop

Answer 11

The gene that makes an embryo into a male causes a specific protein to be produced

When the embryos reproductive system beings to develop, that protein causes the development of testes

The testes then produce male sex hormones which In turn male the rest of the make reproductive system develops

In females the protein is not produced so the embryo develops ovaries and the rest of the female reproductive system

Question 12

Cystic fibrosis

Answer 12

Thick sticky mucus
Breathing difficulty
Chest infections
Difficulty digesting food

And recessive disease
1 in 4 chances of getting it if both parents are sufferers or carriers

Question 13

Huntingtons disease

Answer 13

Dominant disease

Tremors
Clumsiness
Memory loss
Mood changes
Poor concentration 

No cure

50% chance of children inheriting it

Question 14

Genetic testing issues

Answer 14

Not 100% accurate
Errors due to contamination or misinterpretation
False negative / false positive
Not 100% safe could result in miscarriage
Discrimination from employers if find out
Insurance companies may refuse life insurance to people with the wrong alleles

Question 15

Clones

Answer 15

Sexual reproduction produces offspring that are genetically different

Asexual (bacteria, come plants and some animals) make clones - genetically identical

Question 16

How to make clones

Answer 16

Asexual reproduction= 1 parent
Bacteria- divides into 2
Many plants- produce horizontal stones called runners that move out from the base of the plant and form new clones at their tips e.g. Strawberry plants

A few animals r.g. Greenfly, lay eggs which develop into more identical females

Question 17

When embryo split

Answer 17

Identical twins are clones

A single egg is fertilised by a sperm, and an embryo beings to develop as normal

Sometimes the embryo splits into 2, and 1 separate embryos being to develop

2 embryos genetically identical

Question 18

How to clone animal

Answer 18

Nucleus of an egg cell is removed

The nucleus from and adult donor cell is inserted into its place

The cell is stimulated so that it starts dividing as a normal fertilised egg

The embryo produces genetically identical to the donor cell

Question 19

What are stem cells

Answer 19

Most cells in your body are specialised. White blood cells

Multicellular organisms become SPECIALISED in the early stages of development

Some cells are unspecialised. They can develop into types of cells depending on what instructions they are given

UNSPECIALISED = STEM CELLS

Question 20

What are the types of stem cells

Answer 20

Embryonic stem cells=
Unspecialised cells found in early embryo
Stem cells removed from embryo, then the embryo is destroyed

Adult stem cells=
UNSPECIALISED cells that are found in adult animals
They involved in maintaining and repairing old and damaged tissues and can specialise into many cell types but not all
Can be safely removed and no embryo is destroyed

Question 21

What is DNA? What is in the nucleus?

Answer 21

Contains genetic material- 23 pairs of chromosomes in human cells

Each chromosomes has a long molecule of DNA that’s coiled up into a double helix

A gene is a short length chromosome

Genes controls the development of different characteristics