Biology

Question 1

three major purposes of food and energy:

Answer 1

1. Supply the energy for all activities
2. Build new tissue (growth)
3. Repair worn and damaged tissue

Question 2

Three facts about the mouth:

Answer 2

• Chemical and mechanical breakdown
• Chew’s food up into easy-to-swallow balls
• Salivary glands produce Amylase ro start break down

Question 3

Four facts about the oesophagus:

Answer 3

• Partly digested food is swallowed
• Pass down the muscular tube called the oesophagus
• It contracts rhythmically to puch food towards the stomach = peristalsis
• Force of gravity also helps

Question 4

Four facts about the stomach:

Answer 4

• Pummels the food with muscular walls
• Produces pepsin and rennin enzymes
• Pepsin breaks down protein
• Renin coagulates casein, the soluble protein of milk = forming an insoluble curd which is then attacked my pepsin.

Question 5

Why does the stomach produce hydrochloric acid? (4)

Answer 5

• to kill bacteria
• correct pH for the protease enzyme to work
• pH2 = acidic

Question 6

About the small intestine (5):

Answer 6

Main place where digestion happens. The agents of digestion came from 3 sources, including the liver, pancreas and wall of the small intestine. The small intestine is where “food” is absorbed into the blood. It is long and folded to increase surface area. The villi are tiny finger-like things which cover the inner surface to increase surface area.

Question 7

About the pancreas: (3)

Answer 7

The pancreas produces pancreatic amylase which breaks down starch to maltose, trypsin to break down protein and pancreatic lipase to break down fats into fatty acids and glycerol.

Question 8

About the liver: (11)

Answer 8

The liver is the largest organ in the body. Its functions are to act as the chemical factory, stores food and central heating system. Liver stores glucose as glycogen. When the body needs glucose, it turns the glycogen back into glucose. Stores vitamin A, B and D as well as minerals like copper, potassium and iron. They change left overs into waste (urea) and takes poison from blood (germs, alcohol, drugs).The liver makes fibrogen. Produces heat and blood carries it around your body. Bile is produced in the liver but is stored in the gallbladder.

Question 9

About the gall bladder:

Answer 9

Bile is stored in the Gall Bladder, before it is injected into the small intestine.

Question 10

Large intestine:

Answer 10

Where excess water is absorbed from blood.

Question 11

Anus

Answer 11

Where faeces (mostly indigestible food) goes out of the body.

Question 12

What is gas exchange? (2)

Answer 12

• The exchange of oxygen and carbon dioxide.

- And always takes place by diffusion across moist cell membranes.

Question 13

What features do an efficient respiratory surface need? (3)

Answer 13

• The surface area should be as large as possible
• The respiratory surface should be as thin as possible
• The respiratory surface should be moist to allow the gases to dissolve.

Question 14

3 factors of the mammalian respiratory system:

Answer 14

• Air is drawn through the nose and passes into the PHARYNX > LARYNX > TRACHEA > BRONCHI > BRONCHIOLES > ALVEOLI
• The trachea and bronchi are lined with ciliated cells and secreted mucus.
• Particles of dust or bacteria are trapped by this mucus and swept by the cilia back up to the pharynx and swallowed.

Question 15

About the alveoli:

Answer 15

It looks like bunches of grapes.

Question 16

The heart:

Answer 16

A muscular pump with two types of pumping chambers

Question 17

Veins and Arteries:

Answer 17

Form a network of muscular channels carrying blood to and from the heart respectively

Question 18

Pulmonary vessels

Answer 18

Carry blood to and from the lungs

Question 19

Systemic vessels:

Answer 19

Carry blood to and from all other parts of the body

Question 20

Capillaries:

Answer 20

Numerous, very fine channels with thin walls, which provide a very large surface area across which gas exchange of substance can take place.

Question 21

Blood

Answer 21

The circulating fluid consisting of plasma and sells which is highly specialized for transport and defense.

Question 22

What is your muscular pump?

Answer 22

Heart

Question 23

Right atrium:

Answer 23

Receive deoxygenated blood returning from the systemic circuit (body) via the VENA CAVA (vein)

Question 24

Define these words to do with the heart:

• vein
• arteries
• pulmonary

Answer 24

Veins: Into the heart
Arteries: Out of the heart (no valves)
Pulmonary: to do with the lungs

Question 25

Right ventricle:

Answer 25

pumps blood to PULMONARY ARTERY to lungs

Question 26

Left atrium:

Answer 26

Receives oxygenated blood returning from the PULMONARY VEIN

Question 27

Left ventricle:

Answer 27

pumps oxygenated blood to the systemic circuit via the AORTA (artery)

Question 28

How does blood move through the heart?

Answer 28

Blood moves through the heart in one direction because of the presence of the VALVES - between the atria and ventricles.

Question 29

About the heart: (4)

Answer 29

The heart is a powerful muscle slightly larger than a clenched fist. It is composed of four chambers, to upper (the atria) and two lower (the ventricles). it works as a pump to send oxygen rich blood through all the parts of the body. The heart is made out of cardiac muscle which is the only muscle tissue in out body that doesn’t get tired.

Question 30

About the circulatory system: (3)

Answer 30

A transportation system which consists of two diversions. Pulmonary circuit, which consists of all blood vessels withing the lungs and those connecting the lungs with the heart. Systemic circuit, which encompasses the rest of the blood vessels in the body.

Question 31

Controlling body temperature (2)

Answer 31

• All mammals maintain a constant body temperature.
• Animals with a large surface area compared to their volume will lose heat faster than animals with a small surface area.

Question 32

About sweating (5):

Answer 32

When your body is hot, sweat glands are stimulated to release sweat. The liquid sweat turns into a gas (it evaporates). To do this, it needs heat which it gets from your skin. As your skin loses heat, it cools down.

Question 33

About vasodilation (3):

Answer 33

Your blood carries most of the heat energy around your body. There are capillaries underneath your skin that can be filled with blood if your get too hot. This brings the blood closer to the surface of the skin so more heat can be lost (this is why you get a red colour when you are hot).

Question 34

About vasoconstriction (3):

Answer 34

This is the opposite of vasodialtion. The capillaries underneath your skin get constricted (shut off), this takes the blood away from the surface of the skin so less heat can be lost.

Question 35

About piloerection (4)

Answer 35

This is when the hairs on your skin “stand up”. i.e. goose bumps. The hairs trap a layer of air next to the skin which is then warmed by the body heat. The air becomes and insulating layer.

Question 36

About controlling glucose levels:

Answer 36

The body requires glucose in order to create ATP. The amount of ATP demanded will fluctuate. Therefore, the body regulated the availability of glucose to maximise its energy making potential. Two hormones are responsible for controlling the concentration of glucose in the blood - insulin and glucagon. These are both produced in the pancreas.

Question 37

What happens if there is too much or not enough glucose?

Answer 37

• If there is not enough glucose in the blood, Glucagon converts some glycogen (stored in liver) into glucose.
• If there is too much glucose in the blood, insulin converts some of it to glycogen.