ch1 cellular structure and function

Question 1

mitochondria

Answer 1

• site of aerobic cellular respiration
• provides energy to the cell in the form of ATP

Question 2

Chloroplasts

Answer 2

-found in plants and protist cells
- responsible for photosynthesis
- double membrane
- sacks of membrane called grana

Question 2

endoplasmic reticulum

Answer 2

• transports materials around inside the cell.
  1. rough endoplasmic reticulum- studded with ribosomes, tends to modify and transport proteins made by them.
  2. smooth endoplasmic reticulum- lacks ribosomes but do sometimes transport proteins. involved in synthesis and transport of lipids.

Question 2

ribosomes

Answer 2

• found in prokaryotes and eukaryotes
• made of RNA dont have a membrane
• responsible for constructing proteins from amino acids

Question 3

golgi apparatus

Answer 3

• flattened sacks of membrane, called cristernae.
• responsible for final modification of proteins.
• package materials to be secreted into vesicles

Question 4

vacuole

Answer 4

• sacks of membrane used to store materials inside cells
• in animals- small, many, temporary.
• in plants- large, permanent, one of them. used to store water then push the cytoplasm hard up against the membrane

Question 5

lysosomes

Answer 5

contain digestive enzymes to break down and recycle old organelles brought into the cell

Question 5

plastids

Answer 5

• organelles responsible for containing coloured pigment.
• includes chloroplasts (green, photosynthesis), chromoplasts (gives flower colour) , leucoplasts (white, starch storage, protein, fat)

Question 6

cytoskeleton

Answer 6

• structure of fibres made of microtubules and microfilaments.
  -microtubules made of protein called tubulin, forms flagella that allows some cells to move
• microfilaments made of actin, stretchy, allows muscles to contract

Question 7

cell wall

Answer 7

-provide support and stop cells expanding too much.
-fungal cell walls- chitin
- bacterial cell walls- murein
- plant cell walls- cellulose

Question 8

Surface area and volume

Answer 8

• limit on how large cells can be
• too large- exchange of materials becomes too slow for life
• size is limited by rate of diffusion
• volume increases faster than surface area

Question 8

compartmentalization

Answer 8

• organelles in cells form compartments
• different processes which require different conditions can all take place at the same time in the cell.

Question 9

crossing the membrane

Answer 9

substances cross membrane by
- diffusion
- facilitation
- active transport
- endo/exocytosis

Question 9

the plasma membrane

Answer 9

• described by the fluid mosaic model
• is a phospholipid bilayer with embedded proteins and cholesterol.
• phospholipids- phosphate head (hydrophilic head attracted to water)
  and fatty acid tail (hydrophobic tail repelled by water)
  -hydrophilic=lipophobic
  -hydrophobic=lopholic

Question 10

equilibrium

Answer 10

• equal particles in both places.
• diffusion no longer occurs but molecules still move in both directions

Question 11

passive transport

Answer 11

easy

Question 12

active transport

Answer 12

tough

Question 13

simple diffusion

Answer 13

small uncharged or lipid soluble molecules pass straight through the lipid bilayer

Question 13

diffusion

Answer 13

movement of molecules from an area of high concentration to an area of low concentration

Question 14

osmosis

Answer 14

when the substance diffusing is water.
-net movement of water from a dilute solution to a concentrated solution across a semi permeable membrane.

Question 15

facilitated diffusion

Answer 15

• a passive process
• moves molecules down concentration gradients
• carrier molecules or protein channels
• glucose enters cells through facilitated diffusion using carrier protein,

Question 16

active transport

Answer 16

• energy requiring
• moves substances against the concentration gradient
• uses protein channels and carrier proteins
• results in the movement of large and charged atoms, ions and molecules.

Question 17

water and lipid soluble

Answer 17

-water soluble= polar, hydrophilic, lipophobic
-lipid soluble= non-polar, hydrophobic, lipophilic

Question 18

Bulk transport

Answer 18

involves the movement of substances through the formation of vesicles
- requires energy
- out of cell=exocytosis
- into the cell=endocytosis