Cell structure and water

Question 1

function of a plasma membrane

Answer 1

regulates movement of substances in and out of the cell.

Question 2

function of the cell wall

Answer 2

supports plant cells

Question 3

function of nucleus

Answer 3

controls the cells activity.
DNA contains instructions to make protein
the nucleolus makes ribosomes
pores allow substances to move between nucleus and cytoplasm

Question 4

function of lysosome

Answer 4

contains digestive enzymes
can be used to digest invading cells or break down worn out cell components of cells

Question 5

function of ribosomes

Answer 5

site where proteins are made

Question 6

function of RER

Answer 6

folds and processes proteins that were made at the ribosomes

Question 7

function of SER

Answer 7

synthesises and processes lipids

Question 8

function of vesicle

Answer 8

transports substances in and out of the cell

Question 9

function of golgi apparatus

Answer 9

packages new lipids and proteins
Produces vesicles

Question 10

function of mitochondrion

Answer 10

site of aerobic respiration where ATP is produced
found in large cells that are very active and require a lot of energy

Question 11

function of chloroplast

Answer 11

site of photosynthesis

Question 12

function of centriole

Answer 12

involved in separation of chromosomes during cell division

Question 13

function of cilia

Answer 13

microtubules allow the cilia to move
moves substances along the cell surface

Question 14

function of flagellum

Answer 14

microtubules contract and make the flagellum move

Question 15

Protein production in a cell (organelles working together)

Answer 15

-proteins are made at ribosome
-the ribosomes on the RER make proteins that are excreted or attached to cell membrane
-new proteins produced at RER are folded and processed in the RER
-they are then transported from the RER to the golgi apparatus in vesicles
-the proteins are further processed and then enter more vesicles to be transported around the cell

Question 16

main functions of cytoskeleton

Answer 16

-microtubules and filaments support organelles (keeping them in position)
-strengthen the cell and maintain its shape
-responsible of the movement of material in the cell (mitochondria )
-proteins in cytoskeleton cause other cell to move e.g cilia and flagella

Question 17

how to calculate magnification

Answer 17

size of image/size of real object

Question 18

summary of light microscopes

Answer 18

-maximum resolution of 0.2 micrometers
-maximum magnification of x1500
-able to see live whole cells/tissues

Question 19

summary of scanning electron microscopes

Answer 19

-shows the surface of a specimen, seen in 3D
-maximum resolution of 200 nanometers
-maximum magnification of x1500-x2000
-only see dead specimen

Question 20

summary of transmission electron microscopes

Answer 20

-distinguish between small objects
-maximum resolution of 0.5 nanometers
magnification of more than x500,000

Question 21

definition of magnification

Answer 21

how much bigger an image is than the specimen

Question 22

definition of resolution

Answer 22

how well a microscope distinguishes between 2 objects that are close together

Question 23

how is water a polar molecule

Answer 23

the oxygen atom attracts electrons more strongly than the hydrogen atom
slightly negative charge on the oxygen atom and a slightly positive charge on the hydrogen atom

Question 24

how is water a good solvent

Answer 24

allows chemical reactions to occur within cells
metabolites can be transported efficiently
allows prokaryotic cells to exchange substances

Question 25

advantage of water having a high specific heat capacity

Answer 25

due to many hydrogen bonds present- takes alot of thermal energy to break them provides suitable stable habitats in aquatic environments e.g lakes or oceans maintains a constant temperature as water can absorb alot of heat without the temperature fluctuating temps. are optimal for enzyme activity in organisms

Question 26

advantage of water having a latent heat of vaporisation

Answer 26

large amount of thermal energy must be absorbed to break the hydrogen bonds and evaporate provides a cooling effect for living organisms e.g evaporation of water in sweat on the skin

Question 27

advantage of water being less dense than ice

Answer 27

ice floats on water and can act as a habitat for animals such as polar bears ice forms a lattice structure where the water molecules arrange themselves in a very specific and orderly pattern Insulates water beneath for fish and sea creatures

Question 28

Explain how the properties of water are related to the transport role of water in a stem. (3 marks)

Answer 28

cohesion, attracts / holds, water molecules together allows chain of water molecules to be pulled up xylem adhesion allows water molecules, to stick to xylem vessel walls

Question 28

advantage of water being cohesive and adhesive

Answer 28

- allows columns of water to move through xylem of plants and blood vessels in animals -enables surface tension, H bonds create a sort of film on the body of water, allows insects e.g pondskaters to float -adhesion enables water to move up the xylem due to transpiration

Question 29

The rough endoplasmic reticulum is where translation of some proteins takes place in a eukaryotic cell. Describe the structure of the rough endoplasmic reticulum.

Answer 29

* covered with ribosomes * form a network of membranes * phospholipid bilayer