B1- key concepts

Question 1

List the components of both plant and animal cells

Answer 1

• ribosomes
  -mitochondria
  -nucleus
  -cell membrane
  -cytoplasm

Question 2

What is the function of the nucleus?

Answer 2

controlls celular activities and stores genetic information arranged in chromosones

Question 3

What is the structure of cytoplasm

Answer 3

fluid component of the cell that contains oragnelles, enzymes and dissolved ions and nutrients

Question 4

What is the function of cytoplasm

Answer 4

site of cellular reactions anf the i.e first stage of respiration

Question 5

What is the function of mitochondria

Answer 5

Site of later stages or aerobic respiration win which ATP is produced

Question 6

What is the function of the ribosomes

Answer 6

Joins amino acids in a specific order during translation

Question 7

What is a cell wall made of ?

Answer 7

cellulose

Question 8

What does the permanent vacuole contain?

Answer 8

A solution of salts, sugars and organic acids

Question 9

What is the function of the permanent vacuole?

Answer 9

supports the cell, maintiang its turgidity

Question 10

What organelles are found in a prokaryotic cell?

Answer 10

• chromosonal DNA
• Plasmid DNA
• Cell wall
• Cell membrane
• Ribosomes
• Flagella

Question 11

How is genetic information stored in a prokaryotic cell ?

Answer 11

found free within the cytoplasm as:
-chromosonal DNA
-Plasmid DNA

Question 12

What are plasmids?

Answer 12

• small circular loops of DNA found free in the cytoplam and seperate from the main DNA
• carry genes that provide genetic advantages

Question 13

What is a prokrayotic cell wall composed of?

Answer 13

peptidoglycan

Question 14

What is flagellum?

Answer 14

• Long, rotating ‘whip-like’ protusion
• Enables bacteria to move

Question 15

What is a haploid cell ?

Answer 15

A cell that contains a single copy of each
chromosome (half the number of chromosomes)
- e.g. 23 chromosomes in humans

Question 16

What is a diploid cell

Answer 16

A cell that contains two copies of each
chromosome (full set of chromosomes)

e.g. 46 chromosomes in humans

Question 16

What is a diploid cell

Answer 16

A cell that contains two copies of each
chromosome (full set of chromosomes)

e.g. 46 chromosomes in humans

Question 17

what are gametes

Answer 17

They are reproductive cells (haploid)

Question 18

Describe how egg cells are adapted to their function

Answer 18

● Haploid nucleus contains genetic material
● Mitochondria in cytoplasm produce energy for the developing
embryo
● Cytoplasm contains nutrients for the developing embryo
● Cell membrane hardens after fertilisation, preventing the entry
of other sperm and ensuring the zygote is diploid

Question 19

Describe how sperm cells are adapted to their
function

Answer 19

● Haploid nucleus contains genetic information
● Tail enables movement
● Mitochondria provide energy for tail movement
● Acrosome contains enzymes that digest the egg cell
membrane

Question 20

Where are ciliated epithelial cells found?

Answer 20

Found lining the surface of structures such as the respiratory tract and uterus

Question 21

Describe the function of ciliated epithelial cells lining
the airways

Answer 21

Move in synchronised waves to beat mucus (containing dirt and pathogens) up to the back of the throat where it can be
swallowed.

Question 22

What is resolution?

Answer 22

The smallest distance between two
objects that can be distinguished

Question 23

How does a light microscope work?

Answer 23

Passes a beam of light through a specimen which travels through the eyepiece lens, allowing the specimen to be observed.

Question 24

What are the advantages of light microscopes?

Answer 24

- cheap - easy to use - portable - used for live and dead specimens

Question 25

How does an electron microscope work?

Answer 25

It uses a beam of electrons which are focused using magnets. The electrons hit a fluorescent screen which emits visible light, producing an image.

Question 26

Name the two types of electron microscope

Answer 26

- Transmitting electron microscope (TEM) - SCanning electron microscope (SEM)

Question 27

Why do electron microscopes have a greater magnification and resolution?

Answer 27

They use a beam of electrons which has a shorter wavelength than photons of light

Question 28

What are the disadvantages of electron microscopes?

Answer 28

- trainign required for use - only dead specimins - expensive -l arge

Question 29

How do you convert from m to μm?

Answer 29

x 1,000,000 (10^6)

Question 30

How do you convert from m to nm?

Answer 30

x 1,000,000,000 (10^9)

Question 31

How do you convert from m to pm?

Answer 31

x 1,000,000,000,000 (10^12)

Question 32

What molecules enter and leave cells via simple diffusion through the cell membrane?

Answer 32

small molecules : oxygen, water, glucose, amino acids

Question 33

What factors affect the rate of diffusion?

Answer 33

- tempurature - surface area - concentration gradient

Question 34

Define osmosis

Answer 34

movement of water molecules from an area of high water concentration to an area of low water concentration through a partially permeable membrane

Question 35

What is active transport?

Answer 35

The movement of molecules across a cell membrane from an area of low concentration to an area of high concentration, against the concentration gradient, using energy

Question 36

What is diffusion ?

Answer 36

The movement of molecules from and area of high concentraion to low concentration down a concentration gradient

Question 37

What is an advantage of enzymes in the body?

Answer 37

They enable cellular reactions to take place at lower temperatures

Question 38

How can the rate of an enzyme-controlled reaction be calculated when given a value for time?

Answer 38

rate = 1/time

Question 39

what are the units for rate?

Answer 39

S^-1

Question 40

Why must large organic molecules be broken down into smaller, simpler molecules in the body?

Answer 40

● Large molecules are too big to be absorbed across the surface of the gut wall ● ∴ large molecules are broken down into smaller molecules for absorption into the bloodstream

Question 41

Give an example of the breakdown of large molecules into smaller molecules in plants

Answer 41

Starch is broken down by enzymes into simpler sugars which are respired to release energy.

Question 42

What are the monomers of carbohydrates?

Answer 42

simple suars

Question 43

Which group of enzymes catalyses the breakdown of carbohydrates?

Answer 43

Carbohydrases

Question 44

Which type of carbohydrase catalyses the breakdown of starch?

Answer 44

Amylase

Question 45

What are the monomoers of protein?

Answer 45

Amino acids

Question 46

WHich type of enzyme catalyst brewaks down protein?

Answer 46

Protease

Question 47

What is the function of lipases?

Answer 47

Enzymes which catalyse the breakdown of lipids into fatty acids and glycerol

Question 48

Why are small molecules synthesised into larger organic molecules in the body?

Answer 48

Large molecules are used for storage (e.g. glycogen) or are used to build structures (e.g. organelles).

Question 49

Which enzyme catalyses the formation of glycogen from glucose?

Answer 49

Glycogen synthase

Question 50

What is calorimetry?

Answer 50

A method of measuring the heat transfer during a chemical reaction (the amount of energy contained ina food)

Question 51

Describe the method used to measure the amount of energy in a sample of food

Answer 51

1. Add a set volume of water to a boiling tube, record initial temperature 2. Record the mass of a small sample of food (e.g. bean) 3. Stick the sample onto a mounted needle 4. Using a bunsen burner light the food sample 5. Hold the sample under the boiling tube until it burns up 6. Record the maximum temperature reached by the water 7. Record the final mass of the food sample