Key Concepts In Biology

Question 1

What are all organisms?

Answer 1

Prokaryotes of eukaryotes

Question 2

What is in an animal cell?

Answer 2

• nucleus
• mitochondria
• cytoplasm
• cell membrane
• ribosomes

Question 3

What is in a plant cell?

Answer 3

• nucleus
• mitochondria
• ribosomes
• cell membrane
• cytoplasm
• cell wall
• vacuole
• chloroplasts

Question 4

What is in a bacterial cell?

Answer 4

• chromosomal DNA
• ribosomes
• cell membrane
• plasmid DNA
• flagellum

Question 5

What are egg and sperm cells specialised for?

Answer 5

Reproduction

Question 6

How has an egg cell adapted to its function?

Answer 6

• it contains nutrients in the cytoplasm to feed the embryo
• straight after fertilisation, it’s membrane changes structure to stop any more sperm getting in. This makes sure the offspring has the right amount of DNA
• haploid

Question 7

What is a haploid cell?

Answer 7

A cell with a single set of chromosomes, (23 chromosomes)

Question 8

How has a sperm cell adapted to its function?

Answer 8

• has a long tail so it can swim to egg
• mitochondria in the middle to provide energy(though respiration) to swim
• haploid nucleus
• acrosome at the front of the head where it stores enzymes needed to digest its way through the eggs cell membrane

Question 9

Where do you find ciliated epithelial cells?

Answer 9

Lining the surface of organs

Question 10

What are ciliated epithelial cells specialised for?

Answer 10

Moving materials.

Question 11

How do epithelial cells move materials?

Answer 11

The cilia beat to move objects in one direction, along the surface of the tissue

E.g line the airways to help move mucus up the throat to be swallowed

Question 12

When were light microscopes invented?

Answer 12

1590s

Question 13

How do light microscopes work?

Answer 13

Passing light through the specimen. Let us see things like nuclei and chloroplasts and we use them to study living cells

Question 14

When were electron microscopes invented?

Answer 14

1930s

Question 15

How do electron microscopes work?

Answer 15

They use electrons rather than light

Question 16

Why is an electron microscope better?

Answer 16

Higher magnification and resolution ,helps us see smaller things like internal stricter of mitochondria and chloroplasts

Question 17

Equation for total magnification

Answer 17

Total magnification=eyepiece lens magnification x objective lens magnification

Question 18

Equation for magnification

Answer 18

Magnification = image size
——————
Real size

Question 19

Equation for image size?

Answer 19

Image size= magnification x real size

Question 20

How do you convert a millimetre into micrometer?

Answer 20

X 1000

Question 21

How do you convert micrometer into nanometre?

Answer 21

X 1000

Question 22

How do you convert nanometre into picometer?

Answer 22

X 1000

Question 23

How do you convert picometer into nanometre?

Answer 23

Divide by 1000

Question 24

How do you convert nanometre into micrometer?

Answer 24

Divide by 1000

Question 25

How do you convert micrometer into millimetre?

Answer 25

Divide by 1000

Question 26

What are enzymes?

Answer 26

Catalysts produced by living things

Question 27

What is a catalyst?

Answer 27

A substance that increases the speed of a reaction without being used up or changed in the reaction

Question 28

Why do enzymes have special shapes?

Answer 28

So that they can catalyse reactions

Question 29

What fits into an enzymes active site?

Answer 29

A substrate

Question 30

What do enzymes need?

Answer 30

- the right temperature - right pH - right substrate concentration

Question 31

Equation for rate of reaction

Answer 31

Rate = 1000 ———— Time

Question 32

What do digestive enzymes do?

Answer 32

Many molecule in food are too big to pass through the all’s of our digestive system so digestive enzymes break them down, so that they can be absorbed into bloodstream through the walls of the digestive system

Question 33

What do carbohydrases do?

Answer 33

Convert carbohydrates into simple sugars

Question 34

What do proteases to?

Answer 34

Convert proteins into amino acid

Question 35

What do lipases do?

Answer 35

Lipases convert lipids into glycerol and fatty acids

Question 36

How are carbohydrates synthesised?

Answer 36

Joining together simple sugars

Question 37

How are proteins made?

Answer 37

Joining together amino acids, enzymes catalyse the reactions needed to do this

Question 38

What is the test for sugars?

Answer 38

Benedicts reagent

Question 39

What is the test for proteins ?

Answer 39

Biuret test

Question 40

What test is used for lipids

Answer 40

Emulsion test

Question 41

What is the test for starch?

Answer 41

Iodine

Question 42

Equation for energy in food?

Answer 42

Energy in food (j) = mass of water (g) x temperature change of water (degrees c) x 4.2

Question 43

Equation for energy per gram of food

Answer 43

Energy per gram of food = energy in food (j) ——————————- Mass of food (g)

Question 44

What is diffusion?

Answer 44

Is the net (overall) movement of particles from an area of higher concentration to an area of lower concentration

Question 45

What does diffusion happen in?

Answer 45

Liquids and gases

Question 46

What is active transport?

Answer 46

The movement of particles across a membrane against a concentration gradient using energy transferred during respiration

Question 47

What is osmosis?

Answer 47

The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration