Topic 1 - Key Concepts in Biology

Question 1

Purpose of ribosomes

Answer 1

Involved in translation of genetic material in protein synthesis.

Question 2

Vacuole

Answer 2

Contains cell sap, solution of sugar and salts.

Question 3

What type of cell is a bacteria

Answer 3

Prokaryote, no nucleus

Question 4

Chromosomal DNA

Answer 4

Long circular floats in cytoplasm, controls cell activity and replication

Question 5

Plasmid DNA

Answer 5

Small loop of extra DNA for genes like drug resistance.

Question 6

Flagellum

Answer 6

Rotated allowing the cell to move away from toxins and towards nutrients or oxygen

Question 7

Eukaryotes cells

Answer 7

Plant and animal, more complex with nuclei

Question 8

Multicellular organisms

Answer 8

Lots of different types of cells

Question 9

Specialised cell

Answer 9

Cells adapted to their function

Question 10

Sexual Reproduction

Answer 10

Where the nuclei of sperm and egg fuse developing an embryo.

Question 11

Egg cells

Answer 11

Contains nutrients in cytoplasm,
Haploid nucleus
Straight after fertilisation its membrane acts as a barrier to only allow one sperm in.
Haploid

Question 12

Sperm Cell

Answer 12

Long tail to swim to egg.
Many mitochondria to provide energy needed to swim.
Has Acrosome enzymes at front of head to digest through the eggs membrane.
Haploid

Question 13

Ciliated epithelial cell

Answer 13

For moving materials, line on the surface of organs.
Move in one direction across tissue.
Eg. Airways removing mucus.

Question 14

Resolution (microscopes)

Answer 14

How well a microscope distinguishes between 2 close points

Question 15

Advantages of electron microscopes

Answer 15

Higher magnification and resolution.

See smaller images in greater detail.

Question 16

Using a light microscope

Answer 16

1. Thin sample - let’s light through
2. Place sample on slide with a drop of water to secure
3. Add stain if sample is transparent.
4. Place coverslip over sample- press down to remove air bubbles.
5. Use lowest magnification.
6. Move stage up to objective lens using coarse adjustment knob. Work it’s way down until the sample is in focus.
7. Use the fine focus wheel to adjust until the image is focused.
8. If needed increase magnification.

Question 17

Features of a scientific drawing

Answer 17

Clear unbroken lines, no shading or colouring. Use at least half of available space. Label important feature with straight lines which don’t intercept.

Question 18

Total magnification

Answer 18

Eyepiece lens mag x objective lens mag

Question 19

Magnification

Answer 19

Image size

Real size

Question 20

Enzymes

Answer 20

Biological catalysts

Question 21

How enzymes work

Answer 21

Substrate fits into an active site where a chemical reaction splits or joins molecules.

Question 22

Temperature and enzymes

Answer 22

Activity rises until the bonds holding the enzyme together are broken. The active site changes shape so substrate won’t fit. This is denatured

Question 23

PH and enzymes

Answer 23

Has an optimum PH. If PH is too low or too high: bonds in enzyme are interfered with. This changes shape and denatures.

Question 24

Substrate Concentration.

Answer 24

Increases activity until all active sites are occupied.

Question 25

Investigate PH on enzymes

Answer 25

Using amylase turning starch to maltose. Identify the colour iodine solution changes. If starch is present it will be black. Using a buffer solution change the PH and identify the colour it turns starch. More activity = orange

Question 26

Rate of reaction

Answer 26

1000 —-— Measured in s^-1 Times

Question 27

Why must large molecules be broken down

Answer 27

So they can be used for growth and life processes. As they are soluble and can pass through walls

Question 28

Plants and enzymes

Answer 28

Store energy as starch. When needed they use an enzyme to convert to sugars

Question 29

Carbohydrase

Answer 29

Eg. Amylase | Starch to maltose

Question 30

Protease

Answer 30

Convert proteins to amino acids

Question 31

Lipase

Answer 31

Convert lipids to glycerol and fatty acids

Question 32

Carbohydrate synthesis

Answer 32

Joining simple sugars: | Glycogen synthase is an enzyme that joins glucose to make glycogen to store energy

Question 33

Protein synthesis

Answer 33

Joining amino acids

Question 34

Synthesis of lipids

Answer 34

Many enzymes are involved synthesise from fatty acids and glycerol.

Question 35

Test for sugars

Answer 35

Benedict’s solution. Heat to 75C and a coloured precipitate will form. The higher the concentration the more the colour change. From blue to brick red.

Question 36

Starch test

Answer 36

Add iodine solution: If present sample changes from orange to black In not no colour change.

Question 37

Test for Lipids

Answer 37

Emulsion Test: | Shake with ethanol, add water, if milky precipitate forms there are lipids.

Question 38

Test for protein

Answer 38

``` Biuret test: Add Potassium Hydroxide to make it alkaline. Add Copper[II] Sulfate No protein = stay BLUE Protein present = PURPLE ```

Question 39

Calorimetry

Answer 39

Burn dry food until it goes out under a set volume. Use equation: Energy= mass of water x temperature change x 4.2

Question 40

Energy per gram (food)

Answer 40

Energy in food | Mass of food.

Question 41

Diffusion

Answer 41

Net movement of particles from an area of high concentration to low concentration (down concentration gradient)

Question 42

Osmosis

Answer 42

Net movement of water particles across a semi-permeable membrane from a region of high concentration to lower concentration.

Question 43

Purpose of semi-permeable membrane

Answer 43

Only small water particles can move through it leaving larger particles behind. (Eg. Sucrose)

Question 44

Osmosis and solutes (eg.sucrose)

Answer 44

Water try’s to even up the concentration either side of the membrane

Question 45

Active transport

Answer 45

Movement of particles across a membrane against the concentration gradient (h to l) using energy from respiration

Question 46

Active Transport examples

Answer 46

Digestive system | Active transport puts nutrients in the blood even when the gut has a lower concentration.

Question 47

Investigating osmosis

Answer 47

Potatoes in sucrose solution. At 0M of sucrose water moves into the potato to dilute the sucrose. At 1M the water moves out to dilute the solution