IQ2 - Cell Function

Question 1

What are autotrophs?

Answer 1

Autotrophs produce their own food by using inorganic molecules

Question 2

What is cellular respiration?

Answer 2

Cellular respiration is the process where glucose and oxygen are converted into carbon dioxide, water and energy (ATP) for cellular functions

Question 3

What are heterotrophs?

Answer 3

Heterotrophs consume other organisms for energy and also carry out cellular respiration to break down food for energy

Question 4

What raw materials do cells require?

Answer 4

Cells need water, carbon dioxide, lipids, proteins and carbohydrates to function properly

Question 5

Why do cells need to remove waste?

Answer 5

Waste products can be toxic in high concentrations, damaging cells and interfering with cellular reactions

Question 6

How do cells remove waste?

Answer 6

Cells may use diffusion for waste removal or more advanced methods like exocytosis

Question 7

How do you test for glucose?

Answer 7

Benedict’s test

Question 8

How do you test for starch?

Answer 8

Iodine test

Question 9

How do you test for lipids?

Answer 9

Brown paper test

Question 10

How do you test for protein?

Answer 10

Biuret test

Question 11

How do you test for chloride ions?

Answer 11

Silver nitrate test

Question 12

Define enzymes

Answer 12

Globular proteins made of long amino acid chains, catalyse biochemical reactions in cells

Question 13

Define metabolism

Answer 13

Refers to the total of all biochemical reactions that occur within a living organism

Question 14

What are catabolic reactions?

Answer 14

They break down substrates into simpler products

Question 15

What are anabolic reactions?

Answer 15

They build larger molecules from smaller ones, requiring energy input

Question 16

How do enzymes catalyse reactions?

Answer 16

Lower the activation energy needed for a reaction by binding to substrates at their active site

Question 17

What is the lock and key model of enzyme action?

Answer 17

The substrate fits perfectly into the enzyme’s active site, like a key fitting into a lock

Question 18

What is the induced fit model of enzyme action?

Answer 18

The enzyme’s active site molds around the substrate, improving the fit and facilitating the reaction

Question 19

What factors affect enzyme acitvity?

Answer 19

Temperature, pH, concentration of enzyme and substrate and presence of cofactors or inhibitors

Question 20

How does temperature affects enzyme activity?

Answer 20

Higher temperatures increase enzyme activity up to a point around 40 degrees, where they denature

Question 21

What is the optimal temperature for human enzymes?

Answer 21

Human enzymes work optimally between 36-38 degrees

Question 22

How does pH affect enzyme activity?

Answer 22

Each enzyme has an optimal pH, enzymes can be denatured by extreme pH values

Question 23

How do enzyme and substrate concentrations affect enzyme activity?

Answer 23

Higher enzyme concentration speeds up reactions, high substrate concentration will eventually reach a saturation point, where the reaction rate stops increasing

Question 24

What are cofactors and coenzymes?

Answer 24

Cofactors: non-protein molecules (e.g. metal ion, vitamins) that assist in catalysing biochemical reactions
Coenzymes: organic molecules that assist in enzyme catalysis

Question 25

What is enzyme inhibition?

Answer 25

Inhibitors block the enzyme's active site, preventing substrate binding, can be reversible or irreversible

Question 26

What is diffusion?

Answer 26

The net movement of particles from an area of high concentration to low concentration

Question 27

What substances diffuse across the cell membrane?

Answer 27

Small molecules e.g. oxygen, carbon dioxide and glucose

Question 28

How does diffusion occur in cells?

Answer 28

Diffusion occurs due to the random movement of molecules, moving down the concentration gradient

Question 29

What limits diffusion in large organisms?

Answer 29

Diffusion becomes less effective over longer distances and is insufficient in large organisms, which require specialised transport systems

Question 30

How do multicellular organisms adapt to promote diffusion?

Answer 30

For example, the small intestine has villi to increase surface area, aiding faster diffusion of nutrients into the bloodstream

Question 31

What is osmosis?

Answer 31

The spontaneous net movement of water molecules from an area of low solute concentration to high solute concentration across a semipermeable membrane

Question 32

How does osmosis affect cells?

Answer 32

Water moves into or out of a cell depending on whether the external solute concentration is higher or lower than inside a cell

Question 33

What is active transport?

Answer 33

The movement against the concentration gradient (from low to high) requiring ATP

Question 34

What is bulk transport?

Answer 34

Bulk transport moves large molecules or groups of molecules into or out of the cell via vesicles

Question 35

What is exocytosis?

Answer 35

Exocytosis is the process where a vesicle containing substances fuses with the cell membrane to release its contents outside the cell

Question 36

What is endocytosis?

Answer 36

The process where substances are engulfed by the cell membrane and brough into the cell within a vesicle

Question 37

How does diffusion impact cell function?

Answer 37

Diffusion provides cells with oxygen and glucose and removes waste like carbon dioxide

Question 38

What happens if a cell gets too large?

Answer 38

As a cell increases in size, diffusion becomes less efficient, the cell may divide to maintain efficient nutrient and waste exchange

Question 39

Why do larger organisms need specialised transport systems?

Answer 39

Larger organisms have more complex structures and require systems (e.g. circulatory) to transport oxygen and nutrients efficiently

Question 40

What is tonicity?

Answer 40

Tonicity is the environment into which a cell is placed, determining whether it will lose or gain water

Question 41

What is an example of a hypotonic cell, and what is it?

Answer 41

Definition: the inside concentration is higher than outside Example: a cell placed in fresh water

Question 42

What is an example of a hypertonic cell, and what is it?

Answer 42

Definition: inside concentration is lower than the outside concentration Example: cell placed in salt water

Question 43

What is an isotonic cell?

Answer 43

When a cell is placed in a solution with the same concentration as the cell's cytoplasm

Question 44

What happens when an animal cell is placed into a hypotonic solution?

Answer 44

It will swell and burst

Question 45

What happens when a plant cell is placed into a hypotonic solution?

Answer 45

It will gain water and expand to become turgid

Question 46

What happens when an animal cell is placed into a hypertonic solution?

Answer 46

It will shrink in a process called crenation

Question 47

What is the surface area to volume ratio?

Answer 47

Measures how much surface area is available for diffusion relative to the cell's volume

Question 48

How does cell size affect diffusion efficiency?

Answer 48

Smaller cells have higher SA:V ratio, allowing faster diffusion Large cells have lower ratios, slowing diffusion

Question 49

Who do cells needs a high surface area to volume ratio?

Answer 49

A higher ratio allows for more efficient exchange of materials with the environment

Question 50

How does a cell's surface area affect its function?

Answer 50

The larger the surface area, the more material can diffuse across the cell membrane at once

Question 51

What is the role of ATP in active transport?

Answer 51

Provides energy for proteins to move substances against their concentration gradient

Question 52

What is the role of protein pumps in active transport?

Answer 52

Transport substances against their concentration using energy from ATP

Question 53

What are the two types of bulk transport?

Answer 53

Endocytosis and exocytosis

Question 54

How do cells manage osmotic pressure?

Answer 54

By controlling water intake and excretion via processes like osmosis and active transport

Question 55

What is the difference between regular diffusion and facilitated diffusion?

Answer 55

Facilitated diffusion requires membrane proteins to transport molecules across a membrane