Paper 1/ 2: Section 1- Key Concepts in Biology

Question 1

What is the difference between a prokaryotic cell and a eukaryotic cell?

Answer 1

A eukaryotic cell is multicellular and has a nucleus. Prokaryotic cells have no nucleus and are unicellular.

Question 2

What subcellular structures (different parts of a cell) are ONLY in a plant cells and what are their functions?

Answer 2

1. Cell wall- supports/ strengthens the cell.
2. A large vacuole- contains cell sap which maintains the internal pressure (supporting the cell).
3. Chloroplasts- where photosynthesis occurs.

Question 3

What subcellular structures are in bacteria cells and what are their functions?

Answer 3

1. Chromosomal DNA- controls cell activities/ replication.
2. Ribosomes- protein synthesis.
3. Cell membrane- holds cells toghether/ controls what goes in and out.
4. Plasmid DNA- small loops of extra DNA.
5. Flagellum (plural flagella)- movement away from danger and towards beneficial things.

Question 4

What is a specialised cell?

Answer 4

Cells which are adapted to their function.

Question 5

What are red blood cells function and how are they adapted to do so?

Answer 5

RBC’s contain a protein called hemoglobin which carries oxygen around the body.

Question 6

What are sperm cells function and how are they adapted to do so?

Answer 6

Sperm cells transport the male’s DNA to the female’s egg.
. Long tail- to swim to the egg
. Mitochondria in the middle section- provides energy to swim.
. Acrosome at the front of the ‘head’- soes enzymes to digest through the egg cell membrae.
. Contains a haploid nucleus.
.

Question 7

What are egg cells function and how are they adapted to do so?

Answer 7

Egg cells carry the female DNA and to nourish the early stages of the embryo.
. Nutrients in the cyptoplasm- to feed the embryo.
. Changes the structure after fertilisation- to prevent any more sperm getting in.

Question 8

What are muscle cells function and how are they adapted to do so?

Answer 8

Muscle cells help a human being to make movements.
. Cylindrical cells formed of banded fibres that allow contraction.

Question 9

What are ciliated epithelial cells function and how are they adapted to do so?

Answer 9

Ciliated epithelial cells move substances (like mucus).
. Cilia (hair- like structures)- push substances along the tissue surface in one direction.

Question 10

What are root hair cells function and how are they adapted to do so?

Answer 10

Root hair cells enable a plant to absorb minerals and water.
. Large surface area- allows absorption of more water/ minerals.
. Lond and thin- able to penetrate between soil particles.

Question 11

What is a stem cell and a meristem cell?

Answer 11

Stem cell- A cell with the potential to specialise.
Meristem cell- the name for plant stem cells.

Question 12

What is a diploid cell?

Answer 12

A body cell with all chromosomes (23 pairs).

Question 13

What is a haploid cell?

Answer 13

A gamete with half the body cells chromosomes.

Question 14

What is the difference between a light microscope and a electron microscope?

Answer 14

Light Electron
microscope: microscope:
. Uses light . Uses
rays electron rays
. x2000 . x500,000
magnification
. Small and . Large
portable
. Cheaper . Expensive

Question 15

What is resolution?

Answer 15

The clarity of an image.

Question 16

How do you calculate magnification?

Answer 16

Magnification (M)= Image size (I) / Actual size (A)

Question 17

What is the definition of optimum pH?

Answer 17

The ideal pH for an organisms enzyme.

Question 18

What is the Lock and key model?

Answer 18

For an enzyme to work, a substrate has to fit ito the active site. If the substrate’s shape doesn’t fit then the reaction won’t be catalysed.

Question 19

What does it mean for an enzyme to denature?

Answer 19

When the active site changes and the substrate no longer fits into it.

Question 20

What three things affect the rate of reaction?

Answer 20

. Temperature
. pH
. Substrate concentration

Question 21

How do you calculate the rate of reaction?

Answer 21

Rate= 1000/ Time

Question 22

Which 3 essential nutrients does your body need?

Answer 22

. Carbohydrates
. Protein
. Lipids

Question 23

How are these three large molecules broken down into smaller ones?

Answer 23

. Carbohydrates (starch), broken down by amalayse, makes glucose.
. Protein, broken down by protease, makes amino acids.
. Lipids, broken down by lipase, makes glycerol and fatty acids.

Question 24

What is synthesis and enzymes role in synthesis?

Answer 24

Synthesis involves the linking together of large molecules smaller components in correct sequence.
. Some enzymes join these molecules toghether.

Question 25

What is osmosis and does it require energy?

Answer 25

1. Osmosis- Movement of water molecules across a permeable membrane, from a high to low water concentration.
2. It doesn’t require energy.

Question 26

Where does osmosis occur?

Answer 26

Water

Question 27

What is osmosis’ effect on plant cells?

Answer 27

. Becomes turgid in a solution with a higher water potential.
. Cells become flaccid when in a lower water potential.

Question 28

What is osmosis’ effect on animal cells?

Answer 28

. Heavier effect seeing as the have no cell wall.
. Can burst when the tissue fluid has a higher water potential.
. Cells can die when surrounded by a lower water potential.

Question 29

What is diffusion and does it require energy?

Answer 29

1. Diffusion- Movement of particles from a high to low concentration, across the concentration gradient.
2. It doesn’t require energy.

Question 30

Where does diffusion occur?

Answer 30

Fluids (liquids/ gases)

Question 31

What is active transport and does it require energy?

Answer 31

1. Active transport- Movement of particles from a low to high concentration, across the concentration gradient.
2. It does require energy transferred during respiration.

Question 32

Where does active transport occur?

Answer 32

In plants

Question 33

What part does a protein molecule play in active transport?

Answer 33

Proteins embedded in the cell membrane (carrier proteins) help active transport.