bioenergetics

Question 1

uses of glucose

Answer 1

cellular respiration - break down glucose to release energy

make cellulose - used to make strong cell walls

make starch - used to store glucose for a later time

make amino acids - used to make proteins

make lipids - these store energy as fats/oils for later use

Question 2

why did the mass increase after egg placed in water

Answer 2

(mass increased because) water entered by osmosis

from a dilute solution in the beaker to a more concentrated

solution in the egg (cell) through a partially permeable membrane

Question 3

what factors affect the rate of photosynthesis

Answer 3

• temperature
• light intensity
• carbon dioxide availability

Question 4

what does a plateau on a graph say about the factor

Answer 4

• something else is limiting the rate

Question 5

define cellular respiration

Answer 5

an exothermic reaction which transfers energy from glucose, and is continuously occurring and living cells

Question 6

Complete the word equation for anaerobic respiration in plants and fungi:

Answer 6

Glucose ➔ ethanol + carbon dioxide

Question 7

Which organ in the body removes the lactic acid from the blood.

Answer 7

liver

Question 8

Explain why plants with TMV have stunted growth.

Answer 8

less photosynthesis because of lack of chlorophyll
* therefore less glucose made
so
* less energy released for growth
* because glucose is needed for respiration
and /or
* therefore less amino acids / proteins / cellulose for growth
* because glucose is needed for making amino acids / proteins /
cellulose

Question 9

Explain how the human circulatory system is adapted to:
* supply oxygen to the tissues
* remove waste products from tissues.

Answer 9

• dual / double circulatory system which means that it has higher blood pressure and a greater flow of blood to the tissues
• heart made of specialised (cardiac) muscle cells which have long protein filaments that can slide past each other to shorten the cell to bring about contraction for pumping blood
• heart pumps blood to lungs in pulmonary artery so that oxygen can diffuse into blood from air in alveoli
• blood returns to heart via pulmonary vein where muscles pump blood to the body via aorta
• oxygen carried by specialised cells / RBCs which contain haemoglobin to bind oxygen and have no nucleus so there is more space available to carry oxygen
• arteries carry oxygenated blood to tissues where capillaries deliver oxygen to cells for respiration and energy release
• thin walls allow for easy diffusion to cells
• large surface area of capillaries to maximise exchange
• waste products removed eg CO2 diffuse from cells into the blood plasma
• blood goes back to the heart in veins which have valves to prevent backflow
• cardiac output can vary according to demand / is affected by adrenaline

Question 10

why is double circulatory useful

Answer 10

-higher blood pressure and greater flow of blood to tissues

Question 11

how are the muscles in the heart specialized to pump blood?

Answer 11

-layers of specialized cardiac muscle cells that can slide over e/o to shorten cell and bring about muscle contraction for pumping blood

Question 12

blood goes back to the heart through ….. which have …… to prevent …….

Answer 12

-veins
-valves
-backflow

Question 13

blood goes out of the heart to the lungs through …..

Answer 13

-arteries