B2.2 Organisms and Energyy

Question 1

How do glucose and oxygen get to the cells for respiration?

Answer 1

Glucose and oxygen is carried by the blood around the body. The blood also carries away the waste carbon dioxide. These substances move between respiring cells and the capillaries through diffusion. Diffusion happens when particles move from an area where they are in a high concentration to an area where they are in a low concentration. They are diffused over a concentration gradient.

Question 2

How does the concentration gradient remain constant in respiring cells?

Answer 2

Oxygen and glucose levels fall in cells, and oxygen and glucose diffuse from blood to cells.

Carbon dioxide levels rise in cells, and diffused out into the capillaries.

Question 3

Describe the gas exchange.

Answer 3

Kung tissue is made up of alveoli (tiny air sacs). These are surrounded by the capillaries. Oxygen that moves into the body through the lungs, diffuses out of them into the capillaries. Carbon dioxide diffuses into the alveoli and out of the lungs. This movement of gases is called the gas exchange.

Question 4

Why does your heart rate increase during exercise?

Answer 4

The more active a cell is, the more energy it needs so respiration has to happen at an increased rate. This is because the muscles use up the oxygen more quickly, so the blood supply to musicales must increase.

Question 5

What is the formula for cardiac output?

Answer 5

Cardiac output= stroke volume x heart rate.

Question 6

Why does the rate at which we breathe increase during exercise?

Answer 6

An increase of blood supply is of limited use without oxygen, so we need to increase our breath rate.

Question 7

Give the anaerobic respiration chemical equation.

Answer 7

Glucose—> lactic acid+energy. This happens alongside aerobic respiration so that we do not rely solely upon oxygen for energy.

Question 8

Explain EPOC.

Answer 8

After intense exercise, lactic acid needs to be broken down into carbon dioxide and water using oxygen. This means that after exercise excess oxygen is needed to break down the lactic acid. This oxygen is obtained by maintaining a high breathing rate and heart rate after exercise. The time taken for them to decrease to normal is called the recovery time.

Question 9

What is starch?

Answer 9

Starch is a simple carbohydrate which plants can use to store glucose in.

Question 10

Give the photosynthesis reaction

Answer 10

Carbon dioxide+water—->glucose+oxygen

Question 11

Why do plants photosynthesise?

Answer 11

Hey do it to produce their own glucose for respiration because they do not eat anything.

Question 12

Who does chlorophyll help with photosynthesis?

Answer 12

Chlorophyll is stored inside the chloroplasts. It is important for photosynthesis, because this green substance, is what absorbs light for photosynthesis. Chlorophyll transfers the light energy into the stored chemical energy in glucose.

Question 13

How does the large surface area help with photosynthesis?

Answer 13

Leaves are flat and large to absorb as much light as possible for photosynthesis.

Question 14

How do the stomata help with photosynthesis?

Answer 14

On the underside of the lead, tiny spores called stomata open in response to light, allowing carbon dioxide to diffuse from the atmosphere into the plant. The oxygen produced can also diffuse out of the stomata and the water can evaporate.

Question 15

How does the large surface area to volume ratio help with photosynthesis?

Answer 15

The air spaces inside the cell give it a large surface area to volume ratio which makes gas exchange more efficient

Question 16

How does light intensity affect the rate of photosynthesis?

Answer 16

In dim light a plant will photosynthesis slowly because it will not relieve enough light energy for photosynthesis.

Question 17

How does carbon dioxide affect the rate of photosynthesis?

Answer 17

In order for photosynthesis to happen at a fast rate, their needs to be an ample supply of carbon dioxide in order for photosynthesis to occur.

Question 18

How does the temperature affect the rate of photosynthesis?

Answer 18

Temperature affect the rate at which the enzymes work, so in order for photosynthesis to happen effectively, the temperature needs to be optimum for he enzymes.

Question 19

What do the root hair cells do?

Answer 19

The root hair cells have long thin extensions that reach into the surrounding soil, providing a large surface area for substances to enter the cell.

Question 20

How does water Exeter the root hair cells?

Answer 20

Water enters the root hair cells through osmosis. In this process water moves across a partially permeable membrane, from an area where it is in high concentration to an are where it is in lower concentration.

Question 21

What is active transport?

Answer 21

Roots can absorbs nitrates and other substances dissolved in soil, even if the concentration is higher in the plant than in the soil water. Absorbing particles against a concentration gradient is called active transport.

Question 22

How is water transported around plants?

Answer 22

Once the after and minerals have entered the plant through the roots, they need to get up to the plant’s tissues. Xylem a transport the water, and they are specialised tissues formed from dead hollow cells which also give support to the plant. The glucose made by the leaves is converted into sucrose and transported to other parts of the plant through the phloem- strands of living cell tissue.

Question 23

What is transpiration?

Answer 23

Water is evaporated form the surface of the cells inside the leaves, and moves out through diffusion. This maintains a concentration gradient, so more water evaporates and diffuses out of the leaf. The loss of water pulls the water and dissolved mineral salts through the xylem. Factors which increase evaporation will also increase transpiration.

Question 24

What is respiration?

Answer 24

Organisms produce energy in order for reactions to take place inside the cells. This is respiration:

Glucose+oxygen—->carbon dioxide+water+energy.

This is aerobic respiration.

Question 25

What determines where an organism can live?

Answer 25

The conditions of an environment determine where an organism.

Question 26

What do ecologists study?

Answer 26

Ecologists study the biodiversity of life found in an ecosystem or habitat where an organism is found (distribution), and population size.

Question 27

What is sampling?

Answer 27

Sampling is looking at a small portion of an area or population. In random sampling every point within an area has equal chance of being selected, meaning that the sample is representative of the entire area.

Question 28

Describe how you would use a poorer to investigate distribution…

Answer 28

A pooter is used to catch small invertebrates through an inlet tube by sucking sharply on the other tube.

Question 29

How would you collect a sample using a sweep net?

Answer 29

In long grass, a sweep net is used to collect organisms. In ponds a pond net can be used.

Question 30

How would you use a pitfall trap?

Answer 30

Pitfall traps are used for trapping small animals like spiders. These can be set up and left overnight so it is possible to catch organisms which are not act use during the day.

Question 31

How would you use quadrats to collect a sample?

Answer 31

Quadrats are square frames which are used to sample the populations of different species within an area. The quadrat is placed at random, for example by throwing it.

Question 32

What are three environments factor which can affect what organism live in a certain area?

Answer 32

• temperature
• light intensity
• pH