2.Structure And Functions In Living Organisms

Question 1

What is the role of enzymes?

Answer 1

To speed up rates of reaction, biological catalysts in metabolic reactions.

Question 2

How does temperature affect enzyme function?

Answer 2

As temperature increases, so does the rate of reaction because the enzymes and substrates have more kinetic energy so move faster and collide more. However, at a certain temperature the active site of the enzyme denatures and is no longer complimentary to the substrate so rate of reaction slows.

Question 3

How des pH affect enzyme function?

Answer 3

The rate of reaction will increase up to the optimum pH of the enzyme.after the optimum pH of the enzyme the rate of reaction will decrease again.

Question 4

What is diffusion?

Answer 4

The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient.

Question 5

What is osmosis?

Answer 5

The net movement of water across a partially permeable membrane from an area of high water potential to an area of low water potential down a water potential gradient.

Question 6

What is active transport?

Answer 6

The net movement of particles from an area of low concentration to an are of high concentration, against a concentration gradient, using ATP

Question 7

What factors affect the rate of movement of particles?

Answer 7

.surface area
.diffusion distance
.temperature
.concentration

Question 8

How does surface area affect rate of movement of particles?

Answer 8

Larger the surface area, the mor particles can move through in the amaze period of time.

Question 9

How does diffusion distance affect the rate of movement of particles?

Answer 9

Further distance to travel mean a longer time for diffusion

Question 10

How does temperature affect rate of movement of particles?

Answer 10

Higher temp, more kinetic energy, particles move faster

Question 11

How does concentration gradient affect rate of movement of particles?

Answer 11

The larger the concentration, the faster diffusion occurs

Question 12

What form is energy produced in for living organisms when respiring?

Answer 12

ATP

Question 13

What does ATP do?

Answer 13

Provide energy for cells

Question 14

What is the difference between aerobic and anaerobic respiration?

Answer 14

Aerobic respiration uses oxygen, anaerobic doesn’t

Question 15

What is the word equation for aerobic respiration?

Answer 15

Glucose + oxygen —> carbon dioxide + water

C6H12O6 + 6H20 —> 6CO2 + 6H20

Question 16

What is the word equation or anaerobic respiration in animals?

Answer 16

Glucose —> lactic acid (+energy)

Question 17

What is the word equation for anaerobic respiration in plants?

Answer 17

Glucose —> ethanol + carbon dioxide (+energy)

Question 18

What is the role of diffusion in gas exchange?

Answer 18

.to remove the waste products of photosynthesis out of the leaf
.to bring oxygen into the leaf for photosynthesis

Question 19

How is the structure of the leaf adapted for gas exchange?

Answer 19

Stomata- open and close when needed
Guard cells- open and close stomata
Spongy mesophyll- gas diffuses faster in air than through membranes

Question 20

What is the role of the stomata in gas exchange?

Answer 20

To allow gasses to diffuse in and out of the leaf for photosynthesis and respiration

Question 21

What is the role of the xylem

Answer 21

.xylem tubes transport water and minerals
.the xylem carry water and mineral salts from the roots up too the shoot to the leaves in the transpiration stream.

Question 22

How is water absorbed by root hair cells?

Answer 22

.the hairs on the root hair cells increase its surface area for absorption of water
.water is absorbed by osmosis as there is usually a higher water potential in the soil than in the plant

Question 23

What is transpiration?

Answer 23

The evaporation of water from the surface of a plant

Question 24

What factors affect the rate of transpiration?

Answer 24

Humidity, wind speed, temperature, light intensity

Question 25

How does humidity affect the rate of transpiration?

Answer 25

Higher the humidity, lower the rate of transpiration as the concentration gradient from inside the leaf to outside the leaf is lower so less water will diffuse out of the leaf

Question 26

How does wind speed affect rate of transpiration?

Answer 26

Higher the wind speed, higher the rate of transpiration because the water vapour that is exiting the leaf is being swept away allowing a high concentration gradient to be maintained between the inside and the outside of the leaf so the rate of transpiration is higher

Question 27

How does temperature affect the rate of transpiration?

Answer 27

The warmer it is the higher the rate of transpiration When it is warm the water particles have more energy to evaporate and diffuse faster out i of the stomata

Question 28

How does light intensity affect the rate of transpiration?

Answer 28

The brighter th light the higher the rate of transportation as stomata begin to close when it gets darker so when it i bright the stomata will be more open.

Question 29

What are the excretory products of the lungs?

Answer 29

Carbon dioxide and water vapour

Question 30

What are the excretory products of the kidneys?

Answer 30

Urea, ions and water

Question 31

What are the excretory products of the skin?

Answer 31

Sweat - water and salts

Question 32

How des the kidney carry out its role in excretion?

Answer 32

1. Ultrafiltration: .blood from the renal artery flows through the glomeulus .a high pressure is built up which squeezes water, urea, ions and glucose oit of the blood and into the bowman’s capsule .the membranes between the glomerulus and the bowman’s capsule act like filter so bigger molecules like proteins cannot pass through. 2. Reabsorption: .as the filtrate flows along the nephron, useful substances get selectively reabsorbed back into the blood: .all the glucose is reabsorbed from the PCT so that it can be used for respiration. This uses active transport. .sufficient ions are reabsorbed, excess ions aren’t .sufficient eater is reabsorbed from the collecting duct into the bloodstream by osmosis 3. Release of wastes: the remaining substances (water ions and urea) continues out of the nephron, through the ureter and down to the bladder, where it is stored before being released by the urethra.

Question 33

How does the kidney carry out its role in osmoregulation?

Answer 33

.The amount of water reabsorbed bin the kidney nephrons is controlled by ADH (anti-diuretic hormone) .ADH makes the collecting duct mire permeable to water so more water gets reabsorbed back into the blood. .the brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according the how much is needed

Question 34

Describe the structure of the urinary system

Answer 34

Consists of two kidneys, two ureters, which connect the kidneys to the singular bladder which excretes urine through the urethra

Question 35

Describe the structure of the nephron

Answer 35

Glomerulus —> basement membrane —> bowman’s capsule —> PCT —> loop of Henle —> DCT —> collecting duct

Question 36

What is globular filtrate composed of?

Answer 36

Urea, water, ions, glucose

Question 37

Why does selective réabsorptions of glucose occur?

Answer 37

Because glucose is needed for respiration

Question 38

Was is urine composed of?

Answer 38

Urea, ions, water

Question 39

How are organisms able to respond to changes in their environment?

Answer 39

Hormones and nervous control

Question 40

What is homeostasis?

Answer 40

The maintenance of a constant internal environment and the body water content and body temperature are both examples of homeostasis

Question 41

What are the differences between nervous and hormonal control?

Answer 41

Hormonal: .slower response .longer lasting .affect whole organs (more general) .uses the blood .involves hormones Nervous: .faster response .shorter lasting .affects specific parts .uses nerves or neurones .involves nerve impulses

Question 42

What is the CNS made up of?

Answer 42

Brain and spinal chord

Question 43

How is the CNS linked to sense organs?

Answer 43

Nerves

Question 44

When a receptor is stimulated, what happens?

Answer 44

It sends electrical impulses along nerves in an out of the CNS resulting in rapid responses