SAC 1 (cells and cell membrane)

Question 1

cell theory

Answer 1

• all living organisms are made up of cells
• the cell is the most basic unit of life
• all existing cells are produced by other living cells

Question 2

cell membrane

Answer 2

controls what enters and exits the cell

Question 3

cell wall (plant)

Answer 3

helps hold cell structure and protection

Question 4

cytoplasm

Answer 4

jelly substance, that keeps everything suspended and held in place

Question 5

ribosomes

Answer 5

site of protein synthesis

Question 6

golgi apparatus

Answer 6

transport structure, used to transport protein out of the cell

Question 7

rough er

Answer 7

aids proteins, folds and transports

Question 8

smooth er

Answer 8

produces lipids

Question 9

vacuole

Answer 9

stores water and nutrients

Question 10

chloroplast (plant)

Answer 10

site of photosynthesis, absorbs energy from the sun

Question 11

mitochondria

Answer 11

provides energy for the cell, breaks down sugars

Question 12

nucleus

Answer 12

control centre of the cell, hold cell DNA/instructions

Question 13

nucleolus

Answer 13

site where ribosomes are made

Question 14

microtubules

Answer 14

hollow tubes made of proteins, which help strengthen the cell membrane and give it’s shape

Question 15

cillia

Answer 15

hair like structure on animal cell that beat to move from on top of the cell

Question 16

surface area to volume ratio

Answer 16

• greater surface area and smaller volume, or high SA:V, can help a cell exchange materials efficiently with the environment
• times all sides together (length x width x height)

Question 17

cell membrane structure

Answer 17

• arranged as a bilayer
• fatty acid tail - hydrophobic (water hating)
• phosphate head - hydrophilic (water loving)
• transport protein (allows molecules to move in and out of the cell)
• channel protein (ions in and out)(anything with charge)
• carrier protein (glucose)
• cholesterol (makes the membrane more flexible and stronger)
• carbohydrates

Question 18

diffusion

Answer 18

• when molecules move from a high concentration to low concentration
• diffusion occurs until equilibrium is reached

Question 19

simple diffusion

Answer 19

when molecules move directly across the bilayer (lipid soluble molecules) (small molecules/gasses)

Question 20

facilitated diffusion

Answer 20

diffusion that requires transport protein (channel or carrier protein)

Question 21

high and low concentration

Answer 21

the difference between high and low concentration is known as a concentration gradient

Question 22

permeability

Answer 22

• ability of a molecules to move through a barrier
• permeable - molecule can move through
• impermeable - molecule cannot move through

Question 23

solute, solvent, solution

Answer 23

solute - molecules that dissolves
solvent - substance that the solute dissolves in
solution - dissolved solute in solvent

Question 24

osmosis (diffusion/movement of water)

Answer 24

• passive (without energy)
• along concentration gradient (high water to low water)
• across a semi-permeable membrane
• the movement of water from a low solute concentration to high solute concentration

Question 25

hypertonic

Answer 25

- solution with high solute concentration - if solution is hypertonic the water moves out of the cell - in plant cell can cause plasmolysis

Question 26

hypotonic

Answer 26

- solution with low solute concentration - if solution is hypotonic the water move into the cell - in a plant cell can cause turgor

Question 27

isotonic

Answer 27

- solution with the same solute concentration - no overall water movement

Question 28

active transport

Answer 28

- molecules (not water) move against the concentration gradient (low to high concentration) - needs energy in the form of ATP cellular energy

Question 29

endocytosis

Answer 29

- type of active transport - plasma membrane folds around substance to transport it across the membrane into the cell - process: fold, trap, bud

Question 30

exocytosis

Answer 30

- type of active transport - vesicles merge with the plasma membrane to transport materials from the cell - process: vesicular transport, fusion, release

Question 31

prokaryotic and eukaryotic cell

Answer 31

prokaryotic - bacteria - do not have a nucleus or other membrane-bound organelles. Circular DNA. Binary fusion eukaryotic - plant and animal - Contain a nucleus and other organelles that are bound by membranes. Linear DNA.

Question 32

affect of temp on cell membrane and cholesterol

Answer 32

- cholesterol influences the fluidity of the membrane - at high temperatures it decreases and at low temperatures it increases - acts to stabilise the cell membrane - hot - prevents phospholipids from separating - cold - prevents phospholipids from compacting

Question 33

green light transmission

Answer 33

plants appear green because they transmit more green light than they do blue or red

Question 34

villi function

Answer 34

increase absorptive surface area