B2.2

Question 1

What is respiration

Answer 1

An enzyme catalysed reaction that releases the energy needed for us to use and live

Question 2

What happens in aerobic respiration

Answer 2

The glucose in the body reacts with oxygen to form carbon dioxide plus water and energy
Glucose + oxygen —> carbon dioxide + water + energy

Question 3

What does blood need to carry

Answer 3

Glucose and oxygen to the cells and carbon dioxide away from them

Question 4

What happens in diffusion

Answer 4

When particles of a substance spread out, moving from an area of high concentration to an area of low concentration. They diffusé down a concentration gradient

Question 5

What are alveoli and purpose. What is gas exchange

Answer 5

They are tiny sacs that make up the lungs and are surrounded by capillaries. Oxygen comes into the lungs and diffuses through the alveoli and into the blood. As oxygen enters the blood, carbon dioxide leaves it, this is gas exchange

Question 6

Why does exercising increase heart rate

Answer 6

When you exercise, muscle cells are using more energy as muscles are moving more. This means they need more oxygen and need more carbon dioxide to be removed. To do this faster, you breath faster and the heart beats faster to get the blood with oxygen to the muscles fast and to remove the carbon dioxide fast

Question 7

What is stroke volume

Answer 7

The volume of blood pumped per beat

Question 8

What is cardiac output

Answer 8

The volume of blood circulated in the body in a given time, worked out by
Cardiac output = stroke volume x heart rate

Question 9

What happens in anaerobic respiration

Answer 9

Occurs when not enough oxygen

Glucose —> lactic acid + less energy

Question 10

What is epoc

Answer 10

Excess post exercise oxygen consumption. It’s when the body needs to keep breathing heavily after exercise to get oxygen to break down the lactic acid build up from anaerobic respiration

Question 11

What is the recovery time

Answer 11

The time taken for pulse to return to resting levels after exercise

Question 12

What is photosynthesis

Answer 12

The process plants use to make glucose from water and carbon dioxide for energy, using the sun
Carbon dioxide + water —> glucose + oxygen

Question 13

How does photosynthesis work

Answer 13

Photosynthesis is a series of complex catalysed reactions. It occurs in chloroplasts in the leafs. Light enters the leaf and into the chloroplasts. Chlorophyll in the chloroplasts convert light energy into the chemical energy stored in glucose

Question 14

How is starch detected

Answer 14

Iodine solution turns leafs dark blue if starch. Only places with chlorophyll in the leaf will go dark

Question 15

Adaptations of leafs

Answer 15

Lots of chlorophyll for photosynthesis. Large broad thin shape for large surface area so absorb as much light as possible. Underneath are stomata, stoma, these absorb carbon dioxide and release oxygen, doing both through diffusion. Lots of air sacs to give the cells a large surface area to volume ration for efficient gas exchange

Question 16

How can plant growth be maximised

Answer 16

Providing it with optimum conditions for photosynthesis so more glucose can be made which is used for making proteins for growth and respiration

Question 17

What are the four conditions for photosynthesis

Answer 17

Good levels of sun light, good temperature, good amount of water and good amount of carbon dioxide

Question 18

What is a limiting factor

Answer 18

The factor in a reaction that is in lowest supply so not matter how much of the other factors is added, it will remain slow until the limiting factor is increased

Question 19

What are roots for

Answer 19

Anchoring the plant for support, absorbing mineral salts such as nitrates and absorbing water

Question 20

What are root hair cells

Answer 20

Long thin extensions on the surface of roots that provide a large surface area to allow substances to enter the root

Question 21

What happens in osmosis

Answer 21

Water in the ground diffuses into the root hair cells though a semi permeable membrane so only water can get through and not other substances.

Question 22

What is active transport

Answer 22

The movement of substances such as nitrates and other mineral ions dissolved in soil water into the plant even when concentration is greater in the plant than in the soil. Movement of substances against the concentration gradient is active transport and energy is needed for this

Question 23

How are substances such as water and the dissolved mineral ions transported in the plant from the roots.

Answer 23

Specialised cells called xylem grow in elongated shaped. These then die to form hollow tubes in the plant which are used to transport water and mineral ions through it and to support the plant

Question 24

How is sugar transported in leafs

Answer 24

It is first made as glucose in photosynthesis but then converted into sucrose and transported around to other parts of the plant by strands of living tissue Calle phloem

Question 25

What is the process called and how is water moved up a plant

Answer 25

The process is called transpiration. Water that evaporates from cells in the leafs move and diffuse out of the stomata. This means there is less water at the leafs, there is now a conc gradient. This pulls up salt mineral rich water from in the roots through the xylem. Factors that will increase water evaporation in plants will increase transpiration

Question 26

How can too much water kill you

Answer 26

Blood becomes very dilute and causes the brain to swell due to osmosis, this can then cause seizures and even death.

Question 27

How can salt water kill you

Answer 27

Salt in blood causes water to leave cells and make them shrivel and die, the opposite of too much normal water

Question 28

Why do plants become droopy from lack of water

Answer 28

When a plant cell has lots of water surrounding it, it will absorb it all through osmosis. This causes the cell to swell and become rigid, making the plant rigid and upright. When it uses all the water and there isn't any around it, the cells will shrivel and collapse almost making them not as rigid and causing the plant to droop.

Question 29

Why do scientists study the biodiversity of an ecosystem or habitat

Answer 29

To monitor changes in population size of organisms and distribution and to test hypotheses about which organisms live where

Question 30

What is sampling and how is it done

Answer 30

It is studying the biodiversity of a small random area that is then used to represent the whole larger area. Quadrants, square frames of a known size are usually randomly thrown and the area within is what the scientists study.

Question 31

How are small invertebrates captured for studying, insects

Answer 31

A pooter is used. The inlet tube is placed near the specimen and the mouth piece is sharply sucked on to suck the insect into the container through the inlet tube

Question 32

How are nets used to capture specimens

Answer 32

A sweep net can be swept through long grass to catch any organisms living on the grass, similarly, a pond net can be used to sample aquatic habitats

Question 33

He does a pitfall trap work and what is it for

Answer 33

Used to catch small insects such as spiders and beetles. It consists of a hole in the ground with a slightly raised lid. This means when an insect falls into it, it becomes trapped. It can be left overnight for collection

Question 34

How is population estimated in a habitat

Answer 34

Quadrats are thrown and the population of a species is counted, the average number of species per quadrat is used to estimate the total population

Question 35

What is systematic sampling

Answer 35

Sampling done but not in a random way, such as placing quadrats along a line at regular intervals