paper 2

Question 1

What is the definition of homeostasis?

Answer 1

The regulation
of the internal conditions of a cell or organism

Question 2

Why is homeostasis important?

Answer 2

Why is homeostasis important?
To maintain optimum conditions for enzyme

Question 3

List 3 things that are controlled as part of homeostasis.

Answer 3

•blood glucose concentration
•body temperature
•water levels.

Question 4

What is a receptor?

Answer 4

cells that detect stimuli

Question 5

What is an effector?

Answer 5

Muscles or glands, which bring about responses which
restore optimum levels.

Question 6

Name the two parts of the central nervous system.

Answer 6

Brain and spinal cord

Question 7

What is the purpose of the nervous system?

Answer 7

The nervous system enables humans to react to their surroundings and
to coordinate their behaviour.

Question 8

How are messages passed through the nervous system?

Answer 8

Via electrical impulses

Question 9

Put these into the correct order: receptor, effector, sensory neurone, motor neurone, stimulus, response, coordinator.

Answer 9

stimulus, receptor, sensory neurone, coordinator, motor neurone, effector, response

Question 10

What is a synapse?

Answer 10

gap between neurones. Messages are passed by chemical diffusion.

Question 11

What is a reflex action?

Answer 11

Automatic and rapid actions which do not involve the conscious part of the brain.

Question 12

Why are reflex actions important?

Answer 12

To avoid causing more damage to cells.

Question 13

Write out the sequence of a reflex action.

Answer 13

Stimulus, receptor, sensory neurone, synapse, relay neurone, synapse, motor neurone, effector, response

Question 14

Why does a synapse slow down a reflex action?

Answer 14

Because chemical diffusion is slower than electrical impulses

Question 15

How are messages passed in the human endocrine system?

Answer 15

By chemical hormones in the bloodstream

Question 16

Name the 6 glands involved in the endocrine system.

Answer 16

•• pituitary gland
•• pancreas
•• thyroid
•• adrenal gland
•• ovary
•• testes.

Question 18

Compare and contrast the endocrine and the nervous system.

Answer 18

Hormones are slower acting, but the effects are longer lasting.

Question 19

Why is the pituitary gland called the master gland?

Answer 19

It secretes hormones which work on other glands to stimulate the release of other hormones.

Question 20

Name the organ which monitors and controls blood glucose concentration.

Answer 20

Pancreas

Question 21

Name the hormone produced when blood glucose concentration gets too high.

Answer 21

insulin

Question 22

Describe the sequence of events which leads to a return to normal blood glucose if concentration gets too high.

Answer 22

a return to normal blood glucose if concentration gets too high.
If the blood glucose concentration is too high, the pancreas produces the hormone insulin that causes glucose to move from the blood into the cells. In liver and muscle cells excess glucose is converted to glycogen for storage.

Question 23

Describe the sequence of events which leads to a return to normal blood glucose if concentration gets too low.

Answer 23

If the blood glucose concentration is too low, the pancreas
produces the hormone glucagon that causes glycogen to be converted into glucose and released into the blood

Question 24

What is Type 1 diabetes?

Answer 24

A disorder in which the pancreas fails to produce sufficient insulin.

Question 25

What is the treatment for Type 1 diabetes?

Answer 25

Insulin injections

Question 26

What is Type 2 diabetes?

Answer 26

occurs when the body cells no longer respond to insulin produced by the pancreas.

Question 27

What is a major risk factor for Type 2 diabetes?

Answer 27

Obesity

Question 28

How is Type 2 diabetes treated?

Answer 28

A carbohydrate controlled diet and an exercise regime

Question 29

Name the male reproductive hormones and describe their effects during puberty.

Answer 29

Male: testosterone, produced by testes, sperm production begins, voice deepens

Question 30

Name the female reproductive hormones and describe their effects during puberty.

Answer 30

. Female: oestrogen, ovaries, menstrual cycle begins, breasts develop

Question 31

What is ovulation?

Answer 31

Release of an egg from an ovary

Question 32

How long does a mentrual cycle typically take?

Answer 32

Approx. 28 days

Question 33

Describe the roles of FSH, LH, oestrogen and progesterone in the menstrual cycle.

Answer 33

FSH: causes egg to mature in the ovary. LH: causes ovulation. Oestrogen and progesterone: develop and maintain uterus lining

Question 34

List 3 non-hormonal contraceptives.

Answer 34

condoms, copper coil, femidom, diaphragm, spermicidal gel

Question 35

List 3 types of hormonal contraceptive.

Answer 35

Pill, mini-pill, injection, patch, hormonal IUD, implant

Question 36

What is the role of hormones in hormonal contraceptives?

Answer 36

Hormones inhibit maturation and release of egg.

Question 37

What is an IUD and how does it prevent pregnancy?

Answer 37

Copper IUD prevents implantation of a fertilised egg into the uterus

Question 38

Apart from contraceptives describe two other ways inwhich pregnancy can be prevented.

Answer 38

Abstinence (not having sexual intercourse), male and female sterilisation

Question 39

Where is the genetic material found in a cell?

Answer 39

nucleus

Question 41

What is the structure of DNA known as?

Answer 41

Double helix

Question 42

What is a chromosome?

Answer 42

The 3D structure that contains DNA

Question 43

What is a gene?

Answer 43

small section of a chromosome that codes for a sequence of amino acids to make a specific protein

Question 44

What is a genome?

Answer 44

The entire genetic material of that organism

Question 45

Why is understanding the genome important?

Answer 45

To find genes which are linked to diseases such as cancer

Question 46

What is the definition of sexual reproduction?

Answer 46

Reproduction using gametes

Question 47

What is the definition of asexual reproduction?

Answer 47

Reproduction not using gametes to create an identical individual

Question 48

gametes

Answer 48

sex cell

Question 49

Name the gametes in animals and plants.

Answer 49

Animals= Sperm and Egg cells Plants= Pollen and Ovule

Question 50

Which type of reproduction leads to variety within offspring?

Answer 50

Sexual reproduction

Question 51

How can you describe the offspring of asexual reproduction?

Answer 51

clones

Question 52

What is meiosis?

Answer 52

Cell division producing genetically different gametes

Question 53

Why is meiosis important for sexual reproduction?

Answer 53

Each gamete will combine with another to create a unique genome/ genotype

Question 54

Describe a basic outline of what happens during meiosis

Answer 54

Parent cell will copy the DNA and organelles to produce 2 daughter cells. Each daughter cell will then split again to produce 4 haploid (Half DNA) gametes.

Question 55

How is meiosis different from mitosis?

Answer 55

Mitosis produces 2 identical daughter cells but meiosis creates 4 gametes

Question 56

List 3 advantages of sexual reproduction.

Answer 56

produces variation in offspring, meaning a survival advantage if there is an environmental change, sexual reproduction can be used to human advantage in selective breeding.

Question 57

List 4 advantages of asexual reproduction

Answer 57

Only one parent is needed, more time and energy efficient as organisms do not need to find a mate, faster the sexual reproduction, many identical offspring can be produced in favourable conditions.

Question 58

three examples of organisms which use both methods depending on the circumstances.

Answer 58

Malarial parasites reproduce asexually in humans, but sexually in the mosquito. Fungi reproduce asexually by spores, but also sexually to give variation. Many plants produce seeds sexually, but also reproduce asexually by runner or bulb division.

Question 59

How many chromosomes in a human body cell?

Answer 59

23 pairs, 46 individual chromosomes

Question 60

What does the 23rd pair of chromosomes determine?

Answer 60

Sex / gender

Question 61

What are the sex chromosomes for female offspring?

Answer 61

XX

Question 62

What are the sex chromosomes for male offspring?

Answer 62

XY

Question 63

What is an allele?

Answer 63

Different forms of the same gene

Question 64

List 2 things that are controlled by a single gene.

Answer 64

Eye colour, Natural hair colour, Skin colour, tongue rolling

Question 65

What is meant by genotype and phenotype?

Answer 65

Genotype is the combination of alleles in an organism. Phenotype is the observable features of an organism.

Question 66

What is a homozygous genotype and what is a heterozygous genotype?

Answer 66

Homozygous is two copies of the same allele. Heterozygous is different copies of the alleles

Question 67

What would the phenotype be for a cc genotype for red-green colour blindness?

Answer 67

Sufferer of red-green colourblindness

Question 68

What would the phenotype be for a Cc genotype for red-green colour blindness?

Answer 68

Will not have red green colourblindness

Question 69

State the probability of two heterozygous parents having a homozygous recessive offspring.

Answer 69

25%

Question 70

What is polydactyly?

Answer 70

Having extra digits (fingers and toes)

Question 71

What is polydactyly?

Answer 71

dominant allele

Question 72

cystic fibrosis

Answer 72

The build up of mucus on exchange surfaces

Question 73

What causes cystic fibrosis?

Answer 73

recessive allele

Question 74

embryo screening

Answer 74

Taking a sample from the embryo to determine whether it will suffer from a genetic disorder.

Question 75

Describe 2 pros and 2 cons of embryo screening.

Answer 75

Pros: Can evaluate the risk to embryo/mother Parents can make an informed decision about the suffering/lifestyle of their child Cons: Can lead to infection and harm to embryo Ethical implications about terminating unhealthy embryos

Question 76

variation

Answer 76

Differences in the characteristics of individuals in a population

Question 77

What is meant by phenotype?

Answer 77

Phenotype is the observable features of an organism

Question 78

Name one characteristic which is casued by genetic inheritance alone, one that is caused by the environment and one that could be a combination of the two.

Answer 78

Genetic= Tongue rolling, Attached or dangling ear lobes Both= Hair colour, Skin colour, Height, Weight Environment=Accent, language

Question 79

What gives rise to new variants within a population

Answer 79

mutation

Question 80

Do all mutations lead to changes in the phenotype of an organism

Answer 80

Not if the mutation occurs on an area of the DNA that doesnot code for a protein.