2 structure and functions in living organisms B, D, F

Question 1

what is the nucleus?

Answer 1

contains DNA and controls the activities of the cell

Question 2

what is the cytoplasm?

Answer 2

• contains dissolved nutrients and all of the organelles of the cell
• the site of many metabolic reactions

Question 3

what is the cell membrane?

Answer 3

partially permeable barrier that surrounds the cell (allows some substances to move in and out of the cell)

Question 4

what is the cell wall?

Answer 4

• a fully permeable outer layer found in some cells
• plants= cellulose
• fungi= chitin

Question 5

what are the mitochondria?

Answer 5

organelles which are the site of aerobic respiration

Question 6

what are the chloroplasts?

Answer 6

organelles which are the site of photosynthesis

Question 7

what are ribosomes?

Answer 7

organelles which are the sight of protein synthesis

Question 8

what is the vacuole?

Answer 8

• found in plant cells
• contains dissolved nutrients and supports the shape of the cell

Question 9

differences between plant and animal cells:

Answer 9

• plant cells have a cell wall (made out of cellulose)
• plant cells contain chloroplasts
• plant cells have a large vacuole
• plant cells have a fixed shape

Question 10

what is diffusion?

Answer 10

• the net movement of substances from an area of high to low concentration, down a concentration gradient
• can be across a partially permeable membrane

Question 11

what is osmosis?

Answer 11

• the net movement of water particles from an area of high to low water potential, down a water potential gradient
• can be across a partially permeable membrane

Question 12

what is active transport?

Answer 12

• the movement of substances from an area of low to high concentration, against a concentration gradient
• uses energy from ATP

Question 13

what is concentration gradient?

Answer 13

• the difference in concentration between two areas

Question 14

what is energy transferred in the form of?

Answer 14

ATP

Question 15

what does ATP provide?

Answer 15

energy for cells

Question 16

what are the differences between aerobic and anaerobic respiration?

Answer 16

ANAEROBIC RESPIRATION - does not need oxygen
AEROBIC RESPIRATION - needs oxygen

during aerobic respiration, carbon dioxide, water, and ATP are produced

Question 17

word equation and balanced symbol equation for aerobic respiration in living organisms:

Answer 17

word:
glucose + oxygen –> carbon dioxide + water

symbol:
C6H12O6 + 6O2 –> 6CO2 + 6H2O

Question 18

word equation for anaerobic respiration in plants and animals:

Answer 18

glucose + enzymes –> carbon dioxide + ethanol (lactic acid)

Question 19

PRACTICAL: investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms:

Answer 19

• Measure out 10 cm3 of hydrogencarbonate indicator into 3 boiling tubes
• Put in a layer of cotton wool
• Place 10 germinating seeds in tube A
• Place 10 boiled/dead seeds in tube B
• Place 10 glass beads in tube C
• Seal each tube with a rubber bung
• After 3 hours, observe the colour of the indicator
• Hydrogencarbonate indicator is orange in atmospheric CO2 levels
• In high CO2 levels the indicator absorbs the CO2 and becomes yellow
• In low CO2 levels it loses CO2 and becomes purple

Question 20

PRACTICAL: investigate diffusion and osmosis using a non living system:

Answer 20

1. Prepare a range of sucrose (sugar) solutions ranging from 0 Mol/dm3 (distilled water) to 1 mol/dm3
2. Set up 6 labelled test tubes with 10cm3 of each of the sucrose solutions
3. Using the knife, cork borer and ruler, cut 6 equally-sized cylinders of potato
4. Blot each one with a paper towel and weigh on the balance
5. Put 1 piece into each concentration of sucrose solution
6. After 4 hours, remove them, blot with paper towels and reweigh them

Question 21

P2: what is the importance of cell differentiation in the development of specialised cells?

Answer 21

The structural differences between different types of cells enables them to perform specific functions within the organism

Question 22

P2 advantages of using stem cells in medicine:

Answer 22

• potential to treat a wide variety of diseases
• organs developed from a patient’s own stem cells reduces the risk of organ rejection

Question 23

P2 disadvantages of using stem cells in medicine:

Answer 23

• stem cells cultured in a lab could become infected with a virus which then may be transmitted to the patient
• there is a risk of cultured stem cells accumulating mutations that can lead them to developing cancer cells