Genes & Body

Question 0

What does recessive mean?

Answer 0

A version of a gene that will only have an effect if the other one is also recessive

Question 1

What does dominant mean?

Answer 1

A version of a gene that will always have an effect

Question 2

What is the definition of genotype?

Answer 2

The alleles for certain characteristics that are found in an organism

Question 3

What is the definition of phenotype?

Answer 3

The characteristics a certain set of alleles causes

Question 4

What is the definition of homozygous?

Answer 4

If both alleles are the same, the organism is homozygous for that characteristic

Question 5

What is the definition of hetrozygous?

Answer 5

If both alleles are different, the organism is heterozygous for that characteristic

Question 6

Where is DNA found?

Answer 6

In the nucleus of a cell

Question 7

Describe DNA

Answer 7

DNA (inside nucleus) is twisted to form chromosomes

Question 8

Describe a chromosome

Answer 8

Chromosomes (inside DNA) contain genes that code for different characteristics

Question 9

How many chromosomes do humans have?

Answer 9

There are 46 - 23 from each parent

Question 10

How many alleles per gene?

Answer 10

There are always 2 alleles per every gene

Question 11

Describe the conditions of Cystic Fibrosis

Answer 11

Extra sticky mucus
Blocked lungs
Reproductive problems
Breathing problems
Lung infections
Digestive problems
Recessive disease

Question 12

Describe the conditions of Sickle Cell Disease

Answer 12

Poor circulation
Poor oxygen transport
Tired easily
Resistant to Malaria
Recessive disease

Question 13

Describe homeostasis

Answer 13

Homeostasis is the maintenance of a constant internal environment, despite changes in the external environment

Question 14

Give examples of homeostasis

Answer 14

Body temperature
Blood glucose regulation
Water level
Blood salt content
Blood pH

Question 15

What is negative feedback?

Answer 15

The results to up and down but stay roughly constant

Question 16

Describe the process of ‘vaso constriction’ - keeping warm

Answer 16

• The body acts to reduce heat loss
• Hair erector muscles contract and make hair stand upright
• This traps warm air close to the skin
• Sweat glands stop making sweat
• Blood vessels get narrower, less blood near the surface
• This reduces heat loss by radiation

Question 17

Describe the process of ‘vaso dilation’ - cooling down

Answer 17

• The body acts to increase heat loss
• Hair erector muscles relax and make hair lie flat against skin
• Less air is trapped near the surface, more heat is lost by radiation
• Sweat glands make sweat
• This evaporates off skin
• Blood vessels widen, more blood near the surface
• This increases heat loss by radiation

Question 18

Why is controlling body temperature important?

Answer 18

So that your body can function and work properly, for example enzymes need to be at a certain temperature to work

Question 19

How does the body control temperature?

Answer 19

Brain detects temperature
If it’s higher than 37, your body starts sweating
If it’s lower than 37, your body starts shivering

Question 20

What is in the central nervous system?

Answer 20

Brain and spinal chord

Question 21

What is the purpose if a neurone?

Answer 21

To carry electrical messages called impulses

Question 22

What is the speed of a nerve impulse?

Answer 22

15.8 m/s

Question 23

Describe the reflex arc

Answer 23

Stimulus > Receptor > Sensory Neuron > Spinal Chord > Synapse > Relay Neuron > Motor Neuron > Effector > Response

Question 24

What is a synapse?

Answer 24

The point where 2 nerves join - synapses also slow down reactions

Question 25

What is in a vessicle?

Answer 25

It contains a neuro transmitting substance

Question 26

What is a reflex?

Answer 26

A way of protecting yourself - reflexes are something you're born with, they do not involve conscious thought

Question 27

What happens when your blood glucose level is too high?

Answer 27

Your pancreas makes insulin Your blood transports the insulin around your body You liver converts glucose to glycogen

Question 28

Describe Diabetes Type 1

Answer 28

You are born with it | Your body produces no insulin

Question 29

What is the treatment for Diabetes Type 1?

Answer 29

Low sugar diet - avoid sugary food | Injections of insulin

Question 30

Describe Diabetes Type 2

Answer 30

If you eat too much sugary food, your insulin stops working and stops being produced - if you are obese, you have a greater chance if getting diabetes

Question 31

What is the role of insulin?

Answer 31

It lowers your body's blood sugar level

Question 32

What is BMI and how do you work it out?

Answer 32

Body Mass Index mass (kg) ------------- height (m2)

Question 33

Why do diabetics inject insulin about half an hour before each meal?

Answer 33

Because it takes time for the insulin to travel around the body