Mod 1: Cell function

Question 1

What is required by a cell?

Answer 1

gas, nutrients, water, and ions

Question 2

What is need to be discarded by a cell?

Answer 2

wastes and cellular products

Question 3

What determines the permeability of a membrane to a certain product?

Answer 3

size, lipid solubility, electrical charge

Question 4

What is diffusion?

Answer 4

(passive transport)
the net movement of any molecules from a region of high concentration to low concentration of that substance, until equilibrium is reached.
Equilibrium is reached when there is no net movement of molecules in either direction.

Question 5

What is movement along the concentration gradient?

Answer 5

movement from high concentration to low concentration

Question 6

what things can speed up diffusion?

Answer 6

if there is a greater difference in the concentration of substances (steeper gradient)

also heat

Question 7

how does oxygen diffuse across the cell membrane?

Answer 7

oxygen passes through the cell membrane because they are small and neutral. There will constantly be a lower concentration of O2 inside of a cell since it is always being removed du to cellular respiration

Question 8

What is facilitated diffusion?

Answer 8

when molecules pass through the membrane through carrier and channel proteins

Question 9

difference between channel and carrier protein

Answer 9

channel proteins: a narrow passageway for particular ions (always open)
carrier proteins: changes shape to carry molecules from one side of the membrane to the other (depending on concentration gradient)

Question 10

define osmosis

Answer 10

the passive movement of water (water diffusion)
net movement of solvent molecules from regions of high concentration to low concentration through a semipermeable membrane.

Question 11

describe a concentrated solution

Answer 11

high solute concentration
low water concentration

Question 12

describe a dilute solution

Answer 12

high water concentration
low solute solution

Question 13

define solute, solvent, and solution

Answer 13

solute: substance that is getting dissolved
solvent: substance that the solute is getting dissolved in
solution: solute+solvent

Question 14

what are aquaporins?

Answer 14

the pores of a semipermeable membrane where water can go in and out of a cell

Question 15

define hypotonic

Answer 15

when cells are surrounded by a solution that contains a LOWER solute level than the inside of the cell (cytoplasm)

Question 16

define hypertonic

Answer 16

when cells are surrounded by a solution that contains a HIGHER solute level than the inside of the cell (cytoplasm)

Question 17

when is the movement of molecules no longer passive?

Answer 17

when it moves against the concentration gradient. (low concentration to high concentration) which requires energy

Question 18

what is endocytosis?

Answer 18

when a cell engulfs a large particle

Question 19

what is exocytosis?

Answer 19

when a membrane-bound vesicle merges with the cell’s membrane and releases its contents to the extracellular environment

Question 20

what is phagocytosis?

Answer 20

when a cell eats another cell

Question 21

what is pinocytosis?

Answer 21

when the cell membrane engulfs extracellular fluid

Question 22

why is the SA:V ratio of a cell important?

Answer 22

it determines how efficiently substances move into and out of cells.
longer and flatter cells have a higher SA:V than more spherical cells

Question 23

what are the inorganic nutrients a cell needs?

Answer 23

water, mineral salts, and gasesw

Question 24

what are the organic nutrients a cell needs?

Answer 24

carbohydrates, lipids, proteins, and nucleic acids

Question 25

what is the purpose of carbohydrates?

Answer 25

provides cells with energy

Question 26

what is the purpose of lipids?

Answer 26

energy storage, cell structure (protection), hormones

Question 27

what is the purpose of proteins?

Answer 27

(amino acids –> polypeptide chains –> proteins) building block for cells and tissue (eg muscle tissue)
enzymes

Question 28

what is the purpose of nucleic acids?

Answer 28

DNA and RNA
DNA - stores information that controls the cell (main chemical makeup of the nucleus)

Question 29

what are nucleotides?

Answer 29

makes up DNA and RNA
has a phosphate, a sugar and a base
DNA has two strands
RNA has one strand

Question 30

What are enzymes?

Answer 30

biological catalysts that speed up biochemical reactions by reducing activation energy

Question 31

What is metabolism?

Answer 31

ALL chemical reactions within a living organism

Question 32

what is the activation energy?

Answer 32

the minimum amount of energy it takes to start a reaction

Question 33

What is as an active site?

Answer 33

it is where the substrate binds to the enzyme

Question 34

how does temperature affect enzymes?

Answer 34

heat increases the activity of enzymes until it reaches its optimum temperature. if the temp increases, the enzyme activity will decrease until it stops completely.
extremely high temps can destroy the enzyme completely

Question 35

how does pH affect enzymes?

Answer 35

each enzymes has an optimum pH level

Question 36

how does the substrate concentration affect enzymes?

Answer 36

as substrate concentration rises, enzyme activity rises also. enzyme activity increases until it reaches full saturation.

Question 37

How is energy transported within cells?

Answer 37

ATP (adenosine triphosphate)
when energy is required, the ATP bond is broken, releasing a phosphate and ADP (adenosine diphosphate)

Question 38

what are the two stages of photosynthesis? describe them

Answer 38

Light stage and light-independent stage:
Light stage - (in grana) light splits water into O2 and H
Light-independent stage - (in stroma) CO2 and H combine to make glucose

Question 39

difference between aerobic and anaerobic cellular respiration

Answer 39

aerobic = with oxygen
anaerobic = without oxygen