B2-Scaling up

Question 1

Movement of particles- diffusion

Answer 1

• passive
• from an area of high concentration to low concentration
• eg,glucose + oxygen into cells

Question 2

Factors affecting diffusion

Answer 2

• short diffusion area
• higher concentration gradient
• higher surface area

Question 3

Osmosis

Answer 3

Movement of water particles from an area of high concentration to low concentration through a selectively permeable membrane

Question 4

Active transport

Answer 4

-requires atp
-movement of molecules against concentration gradient
Eg.mineral ions into root cells

Question 5

Surface area to volume ratio in small and big animals

and its affect on diffusion

Answer 5

Larger animales have a lower surface area: volume ratio

Increased surface area:volume at exchange surfaces speeds up diffusion

Question 6

Heart blood flow (deoxygenated blood to oxygenated)

Answer 6

Vena cava -> right atrium->right ventricle->pulmonary artery->lungs->pulmonary vein ->left atrium->left ventricle->aorta
-thicker muscle on left as it has to pump blood harder

Question 7

Artery

Answer 7

• blood away from heart

- high pressure->thick walls

Question 8

Vein

Answer 8

• blood to heart

- valves

Question 9

Capillary

Answer 9

• walls one cell, thick

- higher diffusion

Question 10

Blood made up of

Answer 10

• plasma -> carries blood cells
• red blood cell -> oxygen
• white blood cell -> fights disease
• platelet -> clots blood

Question 11

Xylem

Answer 11

• carry water + mineral ions
• made of dead xylem cells
• one way flow

Question 12

Phloem

Answer 12

• carry sugars+ amino acids -> translocation
• sieve plates allowing dissolved sugars to pass through
• two way flow

Question 13

Vascular bundles provid support by

Answer 13

• form a network that supports the softer leaf tissue
• in the stem they are located around the out edge providing the stem with strength to resist bending in the breeze
• in the root they are found in the centre enabling the root to act as an anchor - the root can bend as the plant moves on the wind

Question 14

Transpiration

Answer 14

-water moves through plant in transpiration stream
-rate of transportation (measured using photometer)
-suction effect as water lost from leaves
Low water pressure in the leaves

Question 15

Rate of transpiration affected by

Answer 15

• higher light
• higher temperature
• higher air movement
• lower humidity

Question 16

Mitosis stages

Answer 16

1-DNA replication
2-movement of chromosomes
3-cytokinesis
4-growth of daughter cell

Question 17

Mitosis

Answer 17

• method by which cells replicate

- body cells divide into two genetically identical daughter cells

Question 18

Stem cells

Answer 18

• undifferentiated cells

- divide for growth and repair

Question 19

Where can stem cells be found?

Answer 19

Meristems for plants
Embryonic-found in embryo, can differentiate to make all cells
Adult-found in body tissue (eg.bone marrow), can only make some cells

Question 20

How is a sperm cel specialised

Answer 20

Tail to swim
Mitochondria for energy
Acrosome- enzymes to digest egg membrane

Question 21

How is a fat cell specialised?

Answer 21

-small cytoplasm-> large fat reserve

Question 22

How is a red blood cell specialised?

Answer 22

• no nucleus
• biconcave (high surface area to volume ratio)
• lots of haemoglobin
• carry oxygen
• Small to fit through capillaries

Question 23

How is a ciliated cell specialised

Answer 23

cilia -> move substances along