Biology yr 8

Question 1

capillary

Answer 1

a fine branching blood vessel that form a network between the arteries and veins

Question 2

villi

Answer 2

any of the small, finger-like membrane on your small intestine

used to increase surface area

Question 3

carbohyderate

Answer 3

an organic compound such as sugar or starch, and is used to store energy

cereals, bread, pasta, rice and potatoes

Question 4

lipid

Answer 4

fatty compounds that perform a variety of functions in your body such as storing energy, sending signals through the body, making hormones and more

e.g.cholestrol

butter, oil and nuts

Question 5

protein

Answer 5

large, complex molecules that play many critical roles in the body

e.g. keratin. fish, meat, eggs, pulses, beans, dairy

are used for growth repair, making enzymes, making insulin and more

Question 6

fibre

Answer 6

any elongated, thread-like structure

vegetables, bran (cereal)

undigestible - provides bulk to food so it is easier to push food along by peristalsis

Question 7

vitamin

Answer 7

a group of substances that are needed for normal cell function, growth, and development

fruit, vegetables, dairy foods

to be consumed in small quantities

Question 8

leptin

Answer 8

the hormone that regulates hunger by providing the sensation of satiety (feeling full).

does this to help body maintain a normal weight long-term

Question 9

the organ in which digestion by enzyme is
completed.

Answer 9

small intestine

Question 10

2 parts of the digestive system where physical and chemical digestion take place

Answer 10

mouth and stomach

Question 11

two ways the small intestine is adapted to its function

Answer 11

1. Thin wall - to speed up diffusion / absorption
2. Rich blood supply - carry away absorbed food molecules
3. Covered in villi - increases surface area

Question 12

why food needs to be digested

Answer 12

1. Large food molecules are broken into small molecules
2. These can be reabsorbed through the wall of the small intestine
3. transported in blood to where needed in the body

Question 13

When food hits your stomach, what is the sensation that contributes to a feeling of fullness

Answer 13

stretching

Question 14

What parts of your body are important for sensing the fullness of your stomach?

Answer 14

1. the vagus nerve
   the brain stem
   the hypothalamus

Question 15

hormone released when nutrients and gastrointestinal hormones (hormones that the intestines make) are present in the blood

Answer 15

insulin

Question 16

what cells make leptin?

Answer 16

fat cells

Question 17

why is it that eating more slowly helps you feel fuller?

Answer 17

It gives your body time to release and respond to hormones.

Question 18

peristalsis

Answer 18

• muscle contractions
• It keeps food moving

Question 19

first food group to be digested

Answer 19

carbohyderates

Question 20

digestive enzyme is found in the mouth

Answer 20

salivary amylase

Question 21

why do enzymes need to be at a certain ph level

Answer 21

Each enzyme has an optimum pH range. Changing the pH outside of this range will slow enzyme activity and/or cause it to denature

Question 22

role of bile in digestion

Answer 22

1. breaks down fats into fatty acids, which can be taken into the body by the digestive tract.
2. neutralises stomach acids to regulate Ph levels in the small intestine

Question 23

calorie

Answer 23

a unit of energy that is the amount of energy needed to heat one gram of water by one degree celsius

Question 24

joule

Answer 24

Joule = (mass of water (g) x 4.2 x
temperature difference (°C)) / mass
of food (g)

Question 25

state the role of bacteria in the digestive system

Answer 25

They can
- digest certain substances humans cannot digest
- reduce chance of harmful bacteria multiplying, causing disease
- produce vitamins that humans need e.g. vitamins B & K

Question 26

obesity definition

Answer 26

when the energy input (food you consume) is higher than the output (exercise, physical movement)

Question 27

gall bladder

Answer 27

it stores bile and secretes it into the small intestine

Question 28

Vitamin A function

Answer 28

important for good vision

Question 29

Vitamin C function

Answer 29

the formation of connective tissues (e.g. gums)

Question 30

Vitamin B

Answer 30

the formation of red blood cells

Question 31

Vitamin D

Answer 31

the formation of teeth and bones

Question 32

Vitamin K

Answer 32

helps your blood to clot, if you cut yourself

Question 33

undernutrition

Answer 33

when the energy input (food you consume) is lower than the output (exercise, physical movement)