SB1

Question 1

State the function of the lens, focus wheels, stage and slide of a light microscope

Answer 1

Lens – magnify the image
focus wheel – changes height of the stage allows
focusing
stage -put the slide on here
slide- samples are placed on here for viewing

Question 2

Differences between light and electron microscopes

Answer 2

Light – image create using light. Can only see to a resolution of 200NM (small bacteria).
Electron – image created using electrons. Resolution of 0.2 NM (smaller than viruses.)

Question 3

How to focus on a light microscope

Answer 3

Place the slide on the stage, turn the focus wheel until the image becomes clear

Question 4

How to make a slide (CP)

Answer 4

Add a thin piece of tissue to the slide
Add a stain (iodine/metgyl blue)
Add a cover slip

Question 5

How to calculate magnification from eyepiece objective lens magnification

Answer 5

Magnification of objects lens X magnification of eyepiece lens

Question 6

How to calculate the exercise or something draw/photograph with a microscope

Answer 6

Image size = actual size X total magnification(I= a x m)

Question 7

How to convert unit(important to do before calculating using I = a X m)

Answer 7

M = MM is X 1000
MM = UM is X 1000
UM = NM is X 1000
Divide by 1000 for opposite conversions

Question 8

Define the term resolution

Answer 8

Smallest distance between two points that are separate

Question 9

Define the term magnification

Answer 9

The enlargement of an image compared to the original object

Question 10

Explain how to draw a label scientific drawings

Answer 10

You solid lines – no sketching and no shading
Draw the outline of the cell and organelles
Label with a ruled line with no arrowheads

Question 11

Describe the functions of the nucleus, cell membrane, mitochondria, ribosomes, common to animals

Answer 11

Nucleus – controlled cell, contains genetic
Cell membrane – controls what goes in and out of the
Mitochondria – respiration happens here
Ribosomes– protein making (synthesis)

Question 12

Describe the functions of the cell wall, chloroplast, and vacuole found in the plant cells

Answer 12

Cell wall – provides structure/support
Chloroplast – photosynthesis happens here
Vacuole– stores water

Question 13

State the difference between eukaryotic and prokaryotic

Answer 13

Prokaryotic have nucleus and other organism with membranes

Question 14

State which organelles are found in plant cells but not animal cell

Answer 14

Chloroplast, cell wall, vacuole

Question 15

Explain why why plant and animal cells both need mitochondria

Answer 15

For Respiration

Question 16

How would you tell the difference between plant, animal and bacterial cells?

Answer 16

Plant- look for cell wall/chloroplast
Animal – no cell wall
Bacteria – no nucleus

Question 17

Name specialised cell of the animal that are gametes (sex cells)

Answer 17

Sperm and egg

Question 18

Say and explain the adaptions of a sperm for it role

Answer 18

It is a haploid – has half the genetic information
It has an acrosome at the Head – to release enzymes to penetrate the jelly coat of the egg
It has has a tail – to swim (the flagellum)

Question 19

How does the temperature affect enzyme activity/rate?

Answer 19

As temperature increases, activity/rate increases, up to the optimum temperature. Above this enzyme becomes denatured and activity rapidly decreases.

Question 20

How does the pH affect enzyme activities/rate?

Answer 20

Optimum pH, activities/rate is highest – above and below this activity rapidly changes

Question 21

How does concentration affect enzyme activity/rate?

Answer 21

A substrate concentration increases, the activity increases, but the levels of as at this point, all the enzymes active size contain substrate and cannot react any faster

Question 22

What do these effects look like on graphs?

Answer 22

Temperature – a wave
PH – a Bell shape
Concentration – rapid increase the level off

Question 23

How is rate of enzyme activity calculated?

Answer 23

Rate = change in mass of substrate or product/time

Question 24

State the three processes that move substances into and out of cells

Answer 24

Diffusion, osmosis, active transport

Question 25

Define diffusion

Answer 25

The movement of atoms or molecules(particles) from areas of their high concentration to areas of low concentration through random movement

Question 26

Define osmosis

Answer 26

The movement of water from an area of high concentration(a dilute solution) to an area of its low concentration(a concentration solution) through a partically permeable membrane

Question 27

Define active transport

Answer 27

The movement of molecules across membranes from areas of its low concentration to areas of its high concentration using energy

Question 28

Explain why potato chips and cells change mass when places in a dilute and concentrated solution

Answer 28

Dilute- the cells have a higher solute concentration than the surroundings solution so water moves in by osmosis gaining mas Concentration- the cells have a lower solute concentration than the surroundings solution so water moves out by osmosis lossing mass

Question 29

Describe how to calculate percentage change in mass

Answer 29

Percentage change = (final mass-inital mass)/initial mass x 100

Question 30

Adaptions off egg

Answer 30

It’s a haploid- has half the genetic information It has a jelly coat that will only let one sperm fertilise it and harderns after It has a large, nutrient rich cytoplasm,s for the developing embryo

Question 31

Describe functions of specialised plant cells and how they are specialised for their role

Answer 31

Chromosomal DNA-controls the cell Plasmid DNA-to exchange DNA Flagellum- for movement Cell wall- to protect cell

Question 32

State the kind of united that bacteria cells would be measured in

Answer 32

Micrometers or nanometres

Question 33

How does the size of bacteria relate to plant and animal cells?

Answer 33

Bacteria is much smaller. They are about the size of mitochondrion which fit easily into eukaryotic cells

Question 34

What is an enzyme

Answer 34

An enzyme is a protein that is biological catalyst

Question 35

Describe what the reactions that enzymes catalysts

Answer 35

Enzymes can either make larger molecules from smaller ones or break down larger ones so there smaller

Question 36

What is an active site

Answer 36

An active site is like the slot on an enzyme where its substrate binds into

Question 37

What is a substrate

Answer 37

An enzymes substrate is the molecule that binds with and causes to have a reaction for example amylase

Question 38

What happens when an enzyme denatures

Answer 38

The active site has changes and no longer fits the substrate. The enzyme no longer works so the reaction doesn’t happen

Question 39

What factors affect how rapidly an enzyme woks

Answer 39

Temperature,ph and concentration of substrate effect how quickly the reaction happens