Biology topics 1 and 2

Question 1

State the seven characteristics of life.

Answer 1

M.R.S.G.R.E.N: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

Question 2

What is movement?

Answer 2

A change in position/place.

Question 3

What is sensitivity?

Answer 3

The ability to detect (sense) and respond to changes in the environment + changes in the body.

Question 4

What is respiration?

Answer 4

A series of chemical reactions inside organelles called mitochondria which break down nutrient molecules to release energy.

Question 5

What is growth?

Answer 5

A permanent increase in size of an organism.

Question 6

What is reproduction?

Answer 6

Producing offspring by fertilization or cell cloning.

Question 7

What is excretion?

Answer 7

The removal of toxic/waste substances from the body. Also includes excess, more than the body needs.

Question 8

What is nutrition?

Answer 8

Necessary materials required in the body for growth, development and repair.

Question 9

Give an example of nutrition needed by plants and nutrition needed by humans.

Answer 9

Plants: Light, CO2, water, iron, magnesium

Animals: Carbohydrates, Proteins, iron, sodium, water.

Question 10

Give an example of a substance which is excreted from the human body.

Answer 10

CO2

Question 11

State the structure of an animal cell.

Answer 11

Nucleus, Mitochondria, Cytoplasm, Cell membrane, Ribosomes, Endoplasmic Reticulum.

Question 12

State the structure of a plant cell.

Answer 12

Nucleus, Mitochondria, Cytoplasm, Cell membrane, Ribosomes, Endoplasmic Reticulum, Vacuole, Chloroplasts, Cell wall.

Question 13

What is the function of the cell wall?

Answer 13

The cell wall is made from cellulose, gives the cell support, defines shape, prevents bursting.

Question 14

What is the function of the vacuole?

Answer 14

Contains cell sap, used for storage of materials + support shape of cell. Not enough Cell sap, plant may wilt.

Question 15

What is the function of the chloroplasts?

Answer 15

Contain green pigment called chlorophyll which absorbs light energy for photosynthesis.

Question 16

What is the function of the nucleus?

Answer 16

Contains genetic material in the chromosomes. Controls how cell grows, works + cell division.

Question 17

What is the function of the ribosomes?

Answer 17

Joins amino acids together to make polypeptides.

Question 18

What is the function of the Endoplasmic Reticulum?

Answer 18

Fold the chains made by the ribosomes to build proteins.

Question 19

What are specialized cells?

Answer 19

Cells which have special features, allowing them to carry out their jobs.

Question 20

Give examples of specialized cells.

Answer 20

Palisade mesophyll cell , Red blood cell, Ciliated cell, Sperm and Egg cells, Root hair cell.

Question 21

How are Palisade mesophyll cells specialized?

Answer 21

• Lots of chloroplasts - more photosynthesis
• Large vacuole - push chloroplasts closer to edge.
• Cylindrical shape - compact

Question 22

How are Red blood cells specialized?

Answer 22

Biconcave shape - Larger surface area

No nucleus - more haemoglobin to bind to more oxygen

Question 23

How are Root hair cells specialized?

Answer 23

Large protrusion - larger surface area
No chloroplasts - UNDERGROUND!
Lots of mitichondria - more energy to absorb more minerals
Large vacuole

Question 24

How are Ciliated cells specialized?

Answer 24

Goblet cells - Produce mucus which traps foreign substances.
Hairs called cilia which sweep mucus out.
Lots of mitochondria - more energy to move cilia.

Question 25

How are Sperm cells specialized?

Answer 25

Lots of mitochondria - move flagellum so it can swim more quickly.
Acrosomes - make hole in jelly of Egg cell to get through for fertilization.

Question 26

How are Egg cells specialized?

Answer 26

Cytoplasm - provides nourishment for for the embryo which makes the placenta.
Jelly coating - solidifies after fertilization to prevent other sperm from fertilizing.

Question 27

Equation for working out magnification.

Answer 27

Actual size = Image size/Magnification.

Question 28

What is diffusion?

Answer 28

The net movement of particles from an area of high concentration to an area of low concentration. Down a concentration gradient)

Question 29

How does Temperature affect diffusion?

Answer 29

Increase in temp = more kinetic energy - particles will move more quickly
Therefore rate increases.

Question 30

How does Distance affect diffusion?

Answer 30

Shorter distances = Less area to cover

Therefore rate increases.

Question 31

How does Concentration affect diffusion?

Answer 31

Larger contrast in concentration = Less particles blocking the way.
Therefore rate increases.

Question 32

How does surface area affect diffusion?

Answer 32

Increase in surface area = increase in the amount of fluid diffusing at once.
Therefore rate increases.

Question 33

What is osmosis?

Answer 33

The net movement of molecules from a more dilute solution(high water potential) to a more concentrated solution(low water potential) through a partially permeable membrane.

Question 34

Osmosis in animal cells.

Answer 34

Pure water = Lyse - cell splits

Isotonic water = Crenate - Cell deflates.

Question 35

Osmosis in plant cells.

Answer 35

Pure water = Turgid - Swollen
Isotonic water = Flaccid - not hard, membrane is not pressed tightly against the cell wall.
Plasmolysed - cytoplasm is pulled away from cell wall.

Question 36

What happen to the cells in a potato if they are left in a sugary water?

Answer 36

The cells become Plasmolysed

Question 37

What happen to the cells in a potato if they are left in distilled water?

Answer 37

They become Turgid.