Chapter 1

Question 1

Describe the differences and give examples of prokaryotic and eukaryotic cells?

Answer 1

Eukaryotic cells are complex, these include animal and plant cells. Prokaryotic cells are smaller and simpler (a single- celled organism),these include bacteria cells.

Question 2

Talk about the nucleus

Answer 2

Contains genetic material that controls the activity of the cell. The genetic material is arranged into chromosomes.

Question 3

Talk about the cytoplasm

Answer 3

Gel like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions.

Question 4

Talk about cell membrane

Answer 4

Holds the cell together and controls what goes in and out of the cell.

Question 5

talk about the ribosomes

Answer 5

This is where protein synthesis happens

Question 6

Talk about the mitochondria

Answer 6

This is where most of the reactions for aerobic respiration takes place. Respiration transfers energy that the cell needs to work.

Question 7

Talk about the cell wall

Answer 7

This is rigid and made of cellulose. It supports and strengthens the cell.

Question 8

Talk about the vacuole

Answer 8

Contains cell sap ( a weak solution of sugar and salts) It maintains internal pressure to support the cell

Question 9

Talk about chloroplasts

Answer 9

This is where photosynthesis takes place. They contain a green substance called chlorophyll.

Question 10

What subcellular structures does a bacteria cell have

Answer 10

Chromosomal DNA, Ribosomes, cell membrane, plasmid dna, flagellum

Question 11

Talk about chromosomal DNA

Answer 11

It controls the cells activities and replication, it floats free in the cytoplasm

Question 12

Talk about Plasmid DNA

Answer 12

They are small loops of extra dna that aren’t part of the chromosome. Plasmid contains genes for things like drug resistance and can be passed between bacteria.

Question 13

Talk about the flagellum

Answer 13

A long hair like structure that rotates to make the bacterium move. It can be used to move the bacterium away from harmful substances like toxins and towards beneficial things like oxygen or nutrients.

Question 14

Describe egg cells

Answer 14

It contains nutrients in the cytoplasm to feed the embryo. It has a haploid nucleus. Straight after fertilisation its membrane changes structure to stop any more sperm from getting in. This is to make sure the offspring ends up with the right amount of DNA

Question 15

Describe sperm cells

Answer 15

The function of the sperm cell is to transport the males dna to the females egg. A sperm has a long tail so it can swim to the egg. It has lots of mitochondria in the middle section to provide energy needed to swim. It has an acrosome in the front of its head where it stores enzymes needed to digest its way through the membrane of the egg cell. It also contains a haploid nucleus.

Question 16

Describe ciliated epithelial cells

Answer 16

They line the surface of organs. Some of them have cilia (hair like structures) on the top surface of the cell. The function of the cell is to move substances in one direction across the surface of the tissue eg. move mucus

Question 17

What is resolution

Answer 17

How well you can distinguish two points that are close together. A higher resolution means you can see the image more clearly and in more detail.

Question 18

PRACTICAL: How to use a microscope ( Include making a slide and using the microscope)

Answer 18

Cut a thin slice of epidermal tissue (it needs to be thin to let light pass through it).
Take a clean slide and use a pipette to put one drop of water in the middle of it, this will secure the specimen in place.
Then use tweezers to place the specimen on the slide.
Add a stain (eg iodine) this makes the specimen easier to see.
Place a cover slip over the specimen holding it at an angle.
Press it down gently so that there are no air bubbles.
Then clip the slide onto the stage.
Select the lowest powered objective lens.
Use the coarse adjustment knob to move the stage up, then look down the eyepiece and move the stage downwards until the specimen is in focus.
Adjust the focus with the fine adjustment knob until the image is clear.
If you need to see more, increase magnification with a higher powered objective lens.

Question 19

Name all of the parts of a microscope

Answer 19

Eyepiece lens, coarse adjustment knob, fine adjustment knob, stage, lamp/ mirror, objective lenses, clip

Question 20

Both Formulas for magnification

Answer 20

Magnification = eyepiece lens magnification x objective lens magnification.

Magnification = image size/ actual size.
I
A M

Question 21

Units and how to covert them for microscopy

Answer 21

x 1000 going down
millimetre
micrometer
nanometer
picometer

Question 22

What factors affect the rate of reaction of enzymes

Answer 22

Temperature
Ph
substrate concentration

Question 23

What are enzymes

Answer 23

Biological catalysts which speed up the rate of a reaction without being changed or used up

Question 24

how to calculate the rate of an enzyme reaction

Answer 24

rate = change/time

Question 25

What does carbohydrase do

Answer 25

convert carbohydrates into simple sugars

Question 26

What does protease do

Answer 26

breaks down proteins into amino acids

Question 27

What do lipases do

Answer 27

Convert lipids into fatty acids and glycerol

Question 28

How do you test for sugars

Answer 28

Using benedict’s solution

Add benedict regent (blue) to a sample and heat in a water bath at 75’C

If sugars are present the colour will change to brick red

Question 29

How do you test for proteins

Answer 29

Biuret test

add a few drops of potassium hydroxide to make the solution alkaline

then add copper sulfate solution which is blue

If protein is present, the solution will turn purple

Question 30

How do you test for lipids

Answer 30

Emulsion test

shake the test substance with ethanol for a minute until it dissolves and put the solution into water

if lipids are present, they will precipitate and show up as a milky colour

Question 31

How do you test for startch

Answer 31

iodine

add iodine to the test sample

if iodine is present, it will change from orange/brown to blue-black colour

Question 32

How do you calculate the energy in food

Answer 32

mass of water x temp change x 4.2

Question 33

How do you calculate the energy in food

Answer 33

mass of water x temp change x 4.2

Question 34

How do you calculate the energy per gram of food

Answer 34

energy in food/mass of food

Question 35

What is diffusion

Answer 35

Movement of particles from an area of higher concentration to an area of lower concentration

Question 36

What is active transport

Answer 36

Movement of particles across a membrane from an area of low concentration to an area of high concentration across a partially permeable membrane

Question 37

What is osmosis

Answer 37

Movement of water molecules across a partially permeable membrane from a region of higher water concentration to an area of lower water concentration