Cells Ch1

Question 1

Properties of cell membrane.

Answer 1

• must be small to work efficiently
• has a high SA:V ratio
• controls movement in and out of cell.

Question 2

Plasma membrane

Answer 2

Phospholipid bilayer surrounding the cell.

Question 3

Describe phospholipids and their polarity.

Answer 3

A phosphate-and-glycerol head with fatty acid(s) tail. Head is polar or hydrophilic, tail is non polar or hydrophobic.

Question 4

Fluid mosaic theory

Answer 4

Singer and Nicholson 1972. Plasma membrane is a fluid combination of phospholipids, cholesterol and proteins.

Question 5

Intrinsic proteins

Answer 5

Proteins spanning the entire bilayer, reaches inside of cell, eg channel proteins

Question 6

Extrinsic proteins

Answer 6

Proteins on surface of cell, eg recognition (marker) proteins.

Question 7

State types of proteins in cell.

Answer 7

Recognition, channel and receptor proteins.

Question 8

Receptor proteins.

Answer 8

Recognises and binds specific molecules outside the cell, eg hormones.

Question 9

Recognition proteins

Answer 9

Sticks out from plasma membrane and helps cells to identify each other and foreign bodies.

Question 10

Channel proteins

Answer 10

Assists facilitated diffusion of molecules like glucose.

Question 11

Diffusion

Answer 11

Net movement of substances from high concentration areas to low concentration areas. No energy required.

Question 12

Passive diffusion

Answer 12

Occurs unaided. Movement across cell bilayer.

Question 13

Facilitated diffusion

Answer 13

Aided movement across cell via channel protein.

Question 14

Cell wall.

Answer 14

Surrounds membrane a of plant cells, giving rigidity and structure. Made of cellulose.

Question 15

Active transport

Answer 15

Movement against concentration gradient, using energy from respiration. ATP gets it through as carrier, leaves as ADP.

Question 16

Eukaryotic cells

Answer 16

Cells with membrane-bound organelles.

Question 17

Prokaryotic cells

Answer 17

Cells lacking membrane-bound organelles.

Question 18

Heterotrophic, with example.

Answer 18

Depends on outside sources for energy. Eg, all carnivores, herbivores, omnivores.

Question 19

Autotrophic, with example.

Answer 19

Makes its own energy, eg green plants via photosynthesis.

Question 20

Photosynthetic

Answer 20

Makes energy by converting sunlight, water and CO2 into oxygen and ATP.

Question 21

Chemosynthetic

Answer 21

Conversion of carbon molecules into energy using inorganic molecules (eg, hydrogen gas) as an energy source instead of sunlight.

Question 22

Osmosis

Answer 22

Net movement of liquids from areas of low concentration of solutes to areas of high concentration of solutes. No energy required.

Question 23

Hydrophilic

Answer 23

Water loving, dissolves in water.

Question 24

Hydrophobic

Answer 24

Water hating, doesn’t dissolve in water.

Question 25

Hypertonic

Answer 25

Solution with lower concentration of solutes than outside environment, so water leaves the cell.

Question 26

Hypotonic

Answer 26

Solution with higher concentration of solutes than outside environment, so water enters the cell.

Question 27

Isotonic

Answer 27

Solution outside cell = solution inside cell. No change.

Question 28

Extreme effects on spectrum of tonicity.

Answer 28

Hypotonic: the cell lyses in animal cells, becomes turgid in plant cells.
Hypertonic: the cell shrivels in animal cells, undergoes plasmolysis in plant cells.

Question 29

Endocytosis

Answer 29

Bulk transport of substances into the cell.

Question 30

Exocytosis

Answer 30

Bulk transport of substance out of the cell.

Question 31

Phagocytosis

Answer 31

Solids transported inside cell

Question 32

Pinocytosis

Answer 32

Liquids transported inside cell.

Question 33

Some properties of skin

Answer 33

• regulates temperature
• regulates water
• forms a protective barrier
• stops stuff falling out

Question 34

Nucleus

Answer 34

Control centre of cell; where DNA is found; has a membrane.

Question 35

Mitochondria

Answer 35

Produces all the cell’s energy.

Question 36

Golgi complex

Answer 36

Packages substances in membrane-bound sacs or vesicles to leave cell. Prominent in cells that shift protein out of cell.

Question 37

Ribosomes

Answer 37

Where proteins are made. Are floating freely in cell, or attached to ER. Composed of protein and RNA.

Question 38

Lysosomes

Answer 38

Digestive organelles of the cell, also responsible for programmed cell death (apoptosis).