Cell biology

Question 1

characteristics of eukaryotic cell

Answer 1

nucleus is present.
All membrane bound organelles are present
DNA is enclosed in the nucleus
They are multicellular
DNA is linear
Ribosomes are big
They are big cells
Example: Plants and Animals

Question 2

characteristics of a prokaryotic cell

Answer 2

Nucleus is absent.
Membrane bound organelles are absent.
DNA lies naked in the cytoplasm.
They are mostly unicellular
DNA Is circular
Ribosomes are small
They are small cells.
Example: Bacterial Cell

Question 3

How is DNA stored in prokaryotic cell?

Answer 3

In circular rings called plasmids, and in the cytoplasm

Question 4

How to calculate magnification?

Answer 4

image size /actual size = maginfication

I/A =M

Question 5

Function of the nucleus

Answer 5

It is the brain of the cell
It controls the activities of the cells
It contains DNA which holds our genetic information.

Question 6

Function of ribosomes

Answer 6

to make amino acids for the cells functions

Question 7

Which part of the cell labelled above:
(i) traps light for photosynthesis

Answer 7

chloroplast

Question 8

which part of the cell is made from cellulose

Answer 8

cell wall of plant cell

Question 9

Give one difference between the structure of the bacterial cell and an animal
cell.

Answer 9

Differences between, the DNA,
Bacteria cells - single stranded, in plasmids
Animal cells- linear DNA contained in the nucleus

Question 10

Function of a cell membrane

Answer 10

controls what goes in an out of the cell

Question 11

Function of cytoplasm

Answer 11

Liquid substances where chemical substances take pLace
contains enzymes

that speed up the rate of reaction

Question 12

Purpose of a permanent vacuole

Answer 12

Contains cell sap
Helps the cell stay firm
Found in the cytoplasm

Question 13

what are cell walls made out of?

Answer 13

cell walls are made out of cellulose

Question 14

chloropasts

Answer 14

where photosynthesis takes place
contains chlorophyll where the pigment that traps light

Question 15

Definition of hypotonic

Answer 15

solution where there is low concentration of salt but high levels of water, the cell will gain water through osmosis and gain mass

Question 16

def of hypertonic

Answer 16

solution of high salt concentration but low water concentration, in these solution there is less water outside the cell then inside. Water in the inside will leave the cell to a low concentration and lose mass

Question 17

def of isotonic

Answer 17

equal concentration of salt and water

Question 18

what is diffusion?

Answer 18

movement of particles from a higher to a lower concentration

Question 19

what 3 main factors affect the rate of diffusion?

Answer 19

concentration gradient, the temperature, the hotter means more diffusion,surface area

Question 20

how are unicellular organisms adapted for diffusion?

Answer 20

Large surface area to volume ratio, maximises the area of diffusion

Question 21

formula for surface area to volume ratio

Answer 21

1. find surface area
   Number of sides x length x width
2. find volume
   l x w x h
3. surface area : volume

Question 22

factors of gas exchange

Answer 22

large surface area, thin membrane, good blood supply,

Question 23

def of osmosis

Answer 23

movement of water through a partially permable membrane

Question 24

what is meant by a solution is isotonic to the cell?

Answer 24

the water and salt concentration both inside and outside the cell are the same

Question 25

what is meant when a solution is hypertonic to a cell?

Answer 25

the salt solution outside the cell is higher then inside the cell

Question 26

what is meant when a solution is hypotonic to a cell?

Answer 26

salt solution outside the cell is of a lower concentrate then inside the cell

Question 27

how do plant leaves and stems remain rigid?

Answer 27

through turgor pressure, the water coming in by osmosis causes the vacuole to swell so then the cytoplasam is pushed up against the cell wall

Question 28

definition of active transport

Answer 28

when the concentration wants to go against the concentration gradient which requires energy usually ATP energy

Question 29

how is active transport used in diffusion?

Answer 29

active transport is used when glucose is moved from a low concentration in the gut to a high concentration in the blood to then be used for respiration