CELL BIOLOGY #2

Question 1

what happens in the mitochondria

Answer 1

mitochondria is where respiration takes place

Question 2

what are chromosomes made of

Answer 2

DNA

Question 3

what controls the rate of chemical reactions in the cytoplasm

Answer 3

enzymes

Question 4

Oxygen is taken into cells by the process of?

Answer 4

diffusion

Question 5

Cells need oxygen for?

Answer 5

respiration

Question 6

the parts of cells that use up the most oxygen are the?

Answer 6

Mitochondria

Question 7

Some cells produce oxygen in the process of

Answer 7

Photosynthesis

Question 8

the process by which these gases move into and out of the cell is?

Answer 8

Diffusion

Question 9

The diagrams show what happens to the shape of a plant cell placed in distilled water. Explain why the cell swells and becomes turgid. Name the process involved.

Answer 9

water molecules enter the cell by osmosis

Question 10

Give one feature of the cell wall which allows the cell to become turgid

Answer 10

It is elastic

Question 11

Describe the change which will occur if a piece of peeled potato is placed in a concentrated sugar
solution and explain why this change occurs

Answer 11

The piece of potato will shrink because the concentration of sugar is more than the concentration inside the cell therefore water is drawn out of the cell

Question 12

explain why The barley roots were able to take up more sulfate ions with oxygen than without oxygen.

Answer 12

uptake by active transport ,requires energy more energy from aerobic respiration- there is more energy when oxygen is present

Question 13

How do microvilli and mitochondria help in the active transport of the products of digestion from the small intestine into the blood?

Answer 13

microvilli– large(r) surface area

mitochondria- releases energy

Question 14

Describe two features of the villi which help the small intestine to function.

Answer 14

Large Surface Area- digested food is absorbed quicker

single layer of surface cells

Question 15

Explain the significance of the nucleus in determining the characteristics of the offspring.

Answer 15

the nucleus contains DNA which contributes to half the genes to the offspring

Question 16

Explain one way in which the structure of the leaf mesophyll cell helps it to carry out its job

Answer 16

has chlorophyll/chloroplasts

to absorb light/produce food

Question 17

name the chemical tthat makes the xylem rigid

Answer 17

lignin

Question 18

what is diffusion

Answer 18

is the spreading out of particles of a gas or any substance in a solution

Question 19

what determines the net movement of particles across a cell membrane

Answer 19

the concentration of particles on each side of the membrane

Question 20

what is osmosis

Answer 20

the diffusion of water across a partially permeable membrane from a region of higher water concentration to a region of lower water concetration

Question 21

isotonic meaning

Answer 21

if the two solutions are the same concentrations

Question 22

hypertonic meaningq

Answer 22

a solution that is more concentrated than the cell contents(more solute)

Question 23

hypotonic

Answer 23

the solution that is less concentrated than the cell contents (less solute)

Question 24

what happens to animal cells in a hypotonic solution

Answer 24

they will swell and may burst as water moves in via osmosis

Question 25

what happens to the animals cell if the solution is hypertonic

Answer 25

water moves out of the cell and it shrinks

Question 26

when does turgor pressure occur in a cell

Answer 26

when no more water can enter a cell due to the pressure inside it

Question 27

how can cells be kept rigid

Answer 27

as long as the outside solution is hypotonic water moves into the cell and keeps them rigid

Question 28

what happens to plant cells in a hypertonic solution

Answer 28

they lose water and become flaccid so the plant wilts

Question 29

what is plasmolysis

Answer 29

when the membrane pulls away from the cell wall due to plant cells being put in a hypertonic solution

Question 30

what is active transport

Answer 30

movement of substances against a concentration gradient

Question 31

where does active transport acquire its energy from

Answer 31

respiration

Question 32

why does active transport need energy

Answer 32

to move substances against a concentration gradient

Question 33

what is the difference between diffusion and osmosis

Answer 33

diffusion is the movement of all types of particle from a region of higher to lower concentration

osmosis is the movement of water from a dilute solute solution to a more concentrated solute solution across a partially permeable membrane

Question 34

what are the features of a efficient exchange surface

Answer 34

large surface area
thin walls or short diffusion path
good transport system

Question 35

difference between diffusion and active transport

Answer 35

active transport requires energy and in active transport the movement of particles is against the concentration gradient

diffusion does not require energy and in active transport particles move down the concentration gradient

Question 36

example of active transport in plants

example in a human

Answer 36

absorption of mineral ions by roots

absorption of glucose out of the gut or from kidney tubules in the blood

Question 37

explain in detail what happens to plant cells in a hypertonic solution

Answer 37

water moves out of the cell from a more dilute to the more concentrated solution

the vacuole and the cytoplasm shrink

so the cell membrane draws away from the cell wall and becomes plasmolysed

Question 38

explain why animals that normally live in fresh water may die if placed in sea water

Answer 38

sea water contains salt

so the solution around the animal is hypertonic to its cells

water leaves the cells so chemical reactions in the cytoplasm stops

Question 39

what is turgor pressure and why is it important

Answer 39

when water enters the vacuole in a plant cell creating a pressure called turgor pressure
the cell becomes rigid and this helps to support the plant

Question 40

as organisms increase in size

Answer 40

their surface area to volume ratio decreases

Question 41

why do large organisms need a specialised exchange surfaces

Answer 41

large organisms have a small surface area to volume ratio exchange surfaces allow materials to be passed to a transport system which carries them to all cells

Question 42

how are leaves adapted to increase their surface area

Answer 42

leaves are flat and thin and have internal air spaces and stomata

Question 43

what does more concentrated mean (osmosis)

Answer 43

less water

Question 44

what does dilute mean (osmosis)

Answer 44

more water

Question 45

function of muscle cells in the wall of the body

Answer 45

they contract to churn food

Question 46

why did the students dry the potato before weighing it``

Answer 46

so that any change in mass was not due to the water on the outside of the potato