1.2 transport across cell membranes and 1.6 respiration

Question 1

two main components of a cell membrane

Answer 1

phospholipids
proteins

Question 2

what is a selectively permeable membrane

Answer 2

describe the membrane that contains channel forming proteins that allow molecules to travel directly across membrane through pores. it is describes as selectively permeable because the size of pores created by channel forming proteins controls the size of the molecules that can travel through eg small molecules eg water can move through but large molecules like starch cannot

Question 3

function of proteins in membrane

Answer 3

enzymes - speed up chemical reactions inside cells
hormone receptors- to receive and respond to specefic hormone messages
channel forming proteins- structural part of membrane that allows the transport of molecules across membrane
carrier proteins- structural part of membrane that is involved with active transport of molecules across membrane

Question 4

passive transport

Answer 4

movement of substances down a concentration gradient from earin of high concentration to a area of low concentration THIS DOES NOT REQUIRE ENERGY

Question 5

define consent ration gradient

Answer 5

the gradient differs to the difference between the two gradients the greater the diff in two concentrations the steeper the gradient is going to be

Question 6

two examples of passive transport

Answer 6

diffusion
osmosis

Question 7

diffusion

Answer 7

the movement of molecules from a higher concentration gradient to a lower concentration gradient

Question 8

examples of substances that can enter and exit cells by diffusion

Answer 8

O2
CO2
glucose

Question 9

importance of diffusion in organisms

Answer 9

glucose and oxygen will diffuse into cells as these are raw materials needed for aerobic respiration

co2 will diffuse out of cells as this is a waste product for respiration

Question 10

definition of osmosis

Answer 10

the movement of water molecules from a higher water concentration to a lower water concentration through a selectively permeable membrane

Question 11

effects of osmosis on animal cells in diff solutions

Answer 11

if animal cells are placed on a solution with a higher water concentration than the content of the cells they will gain water by osmosis and eventually burst when the cell membrane is stretched so far that it ruptures

if an animal cell is placed in solution with a lower water concentration than the cells then the water will move out of cells by osmosis and the cells will shrink

Question 12

effects of osmosis on plant cells in diff solutions

Answer 12

if plant cells are places in solution with a higher water concentration that the context of cells they will gain water by osmosis and the cells will swell and become turgid

if plant cells are places in solution with a lower water concentration than the content of the cells then the water will move out of cells by osmosis and gen cell will become plasmalused

Question 13

active transport

Answer 13

movement of molecules and ions across the cell membrane against the concentration gradient using membrane proteins and energy

Question 14

role of membrane proteins in movement of molecules ions by active transport

Answer 14

operate as carriers that pick up and transport molecules ions from one side of membrane where they are in a low concentration and move them to the other side of the membrane where they are released into high concentration

Question 15

substances that move by active transport

Answer 15

ions such as sodium Na possasum K chloride CI we magnesium Mg move by active transport

Question 16

compare actuve and passive transport in terms of energy requirements

Answer 16

passive - requires no energy
active transport requires energy

Question 17

respiration definision

Answer 17

is a series of enzyme controlled chemical reactions that releases the chemical energy stored in glucose

Question 18

chemicals that control the rate of respiration

Answer 18

the chemical energy released by glucose by respiration is used to generate a chemical calledATP THIS ATP is then used to transfer energy to other chemicals reactions inside the cellsb

Question 19

examples of cellular activities that require energy transferred by Atp

Answer 19

muscles cell contraction
cell division
protein synthesis
transmission of nerve impulses

Question 20

respiration pathways

Answer 20

respiration in presence of oxygen- aerobic respiration

respiration in the absense of oxygen- fermintation pathway

Question 21

chemicals first realeased in first stage of respiration

Answer 21

glucose is broken down to release two molecules of pyrovate and a small quantity of energy in the form of 2 molecules of ATP

Question 22

summary word equation for aerobic respiration

Answer 22

glucose + oxygen —-> carbon + water + energy

Question 23

word equation for fermentation in yeast and animal cells

Answer 23

animal- glucose -»» lactate + energy

plants- glucose —-»> carbon dioxide + ethonal + water

Question 24

compare aerobic and fermentation in terms of breakdown products and energy release

Answer 24

breakdown products
aerobic - carbon water and atp
feemintation in animals- lactase and atp
fermi station in plants- ethanol carbon dioxide and atp

energy released
aerobic- large number of ATP molecules
fermentation in animals- low number of Atp
plants- small number of atp

Question 25

compare aerobic and fermentation in terms of their locations inside cells

Answer 25

all respiration pathways begin in cell cytoplasm of oxygen is present then aerobic respiration is completed in mitochondria if oxygen is absense then the process of fermentation is completed in cytoplasm

Question 26

link between energy requirements of cell and the number of mitochondria present in that cell

Answer 26

the hugher the energy requirement for the cell the greater the number of mutochondrai present in cell. This is bc the higher the number of mitochondria means that cell can do more aerobic respiration therefore make more atp to supply greater energy for cell Ecample - sperm, muscle and liver contain high number of mitochondria because they are all very active cells compared to the small number of mitochondria found in relatively inactive skin cells