B123

Question 0

What is the difference between genotype and phenotype?

Answer 0

Genotype is the genes someone has. Phenotype are the characteristics someone shows.

Question 1

What is the function of a gene?

Answer 1

To code for a specific protein. Some are structural and make up the body. Others are functional, and do things. Like enzymes.

Question 2

Why do children look a bit like both their parents?

Answer 2

They inherit genes from both their parents, but only one copy from both. These mix up randomly, thus a child looks a little like both.

Question 3

What is the difference between homozygous and heterozygous?

Answer 3

Homozygous = same alleles for a trait.
Heterozygous = different alleles for a trait.

Question 4

Explain how alleles combine to produce a phenotype.

Answer 4

Two/One dominant alleles: Trait is shown.
One recessive: no trait shown.
Two recessive: trait is shown.

Question 5

How do genes determine how gender develops?

Answer 5

The Y chromosome carries a gene which causes the production of a protein which itself causes testes to be produced. If it is not present, ovaries are produced.

Question 6

What are the symptoms of cystic fibrosis?

Answer 6

Sticky mucus, breathing difficulty, chest infections, difficulty in digesting food.

Question 7

What are the symptoms of Huntington’s disease?

Answer 7

Tremors, clumsiness, amnesia, mood changes, poor concentration.

Question 8

In what three ways can genetic testing occur?

Answer 8

When embryos are produced by IVF, they an be tested and selected.
Children and adults can be tested for diseases.
Children and adults can be tested before drugs a re prescribed.

Question 9

What issues are associated with genetic testing.

Answer 9

Accuracy, safety, children, family, abortions, discrimination, insurance

Question 10

What is a clone? How do they occur in nature?

Answer 10

A clone is a genetically identical organism.
They occur in nature in a few ways: Bacterial mitosis, greenflies, runners, bulbs,identical twins. They can also be produced artificially.

Question 11

What is the difference between embryonic and adult stem cells?

Answer 11

Embryonic -> can be come anything. Totipotent.

Adult -> They can become some things, but not everything.

Question 12

How can symptoms be caused?

Answer 12

By cell damage or toxins.

Question 13

How do antibodies fight infection?

Answer 13

They either:
Mark microorganisms
Bind to and neutralise toxins
Kill bacteria directly.

Question 14

How does vaccination work?

Answer 14

You are injected with a non-harmful form of a microbe. Your body produces antibodies to attack them. Your memory cells remember how to attack them so if you are infected, the antibodies are produced very quickly.

Question 15

Why should we always finish antibiotics courses?

Answer 15

Antibiotics create a situation where resistant bacteria have an advantage, causing rapid evolution.

Question 16

Describe the drug trial process.

Answer 16

They are developed using human cells, then tested on two species of mammal. They are then given to human volunteers and finally to sufferers of the disease to be cured. Blind trials, open-label trials, double-blind trials and placebos are all used.

Question 17

How are the three blood vessels specialised for their own jobs?

Answer 17

Arteries have strong walls to deal with the high pressure.
Veins have valves to keep blood flowing correctly.
Capillaries have walls just a cell thick to allow easy diffusion.

Question 18

How is blood pressure expressed?

Answer 18

Two values - a higher value when the heart contracts and a lower value when it relaxes.

Question 19

What lifestyle factors can increase the risk of heart disease?

Answer 19

Poor diet, smoking, misuse of drugs, excessive alcohol drinking, stress

Question 20

What is homeostasis?

Answer 20

Balancing inputs and outputs to maintain a constant internal environment.

Question 21

What three things are invoked in a general negative feedback loop?

Answer 21

Receptor, processing centre, effector.

Question 22

What are the inputs and outputs for water?

Answer 22

Inputs: drinks,food respiration
Outputs: sweating,breathing, faeces,urine

Question 23

How do the kidneys control water?

Answer 23

They filter small molecules from the blood. They reabsorb a lot of things. Whatever isn’t reabsorbed becomes urine.

Question 24

What things affect the consistency of urine?

Answer 24

External temperature, exercise, intake of fluids and salts.

Question 25

How do drugs affect ADH production?

Answer 25

Alcohol results in a large amount of more dilute urine.

Ecstasy results in small amount of more concentrated urine.

Question 26

What is a species?

Answer 26

A group of organisms that can breed to produce fertile offspring.

Question 27

What are the similarities and differences between natural selection and selective breeding?

Answer 27

Natural selection: characteristics that are good for survival.
Selective breeding: whatever humans want.

Question 28

Contrast Darwin’s and lamarck’s ideas on evolution.

Answer 28

Darwin proposed evolution through natural selection. Lamarck proposed that if a characteristic was used a lot by an animal then it would be more developed. He was very wrong.

Question 29

What does biodiversity include? Why is it important?

Answer 29

Biodiversity includes he number of different species, the range of species,a nd the variation within the species. It is important because we need resources to make food crops and medicines.

Question 30

What are the five main kingdoms of animals?

Answer 30

Bacteria, fungi, algae plants and animals.

Question 31

How May extinction be caused?

Answer 31

Environmental conditions could change, a new species could be introduced or a foodstuff could become extinct.

Question 32

What is the formula for the efficiency of energetic transfer?

Answer 32

Energy in second stage * 100 all over energy in first stage

Question 33

Draw a diagram of the carbon and nitrogen cycles. Obviously I can’t really explain them here not enough space.

Answer 33

Sure.

Question 34

Name six things with which environmental change can be measured.

Answer 34

Non living: temperature, nitrate level, co2 level.

Living: lichen, mayfly nymphs, phytoplankton.

Question 35

What is sustainability? How can packing materials be made more sustainable?

Answer 35

Meeting the needs of today’s population without harming the environment so that future generations can meet their own needs. Packing materials can be made using renewable materials, using less energy and creating less pollution.