Life processes at a the cellular level

Question 1

What is a Cell Wall?

Answer 1

Rigid structure which provides support to cells, composed of cellulose in plant cells

The cell wall is crucial for maintaining cell shape and protecting against mechanical stress.

Question 2

What is a Chloroplast?

Answer 2

Organelle found in the cytoplasm of photosynthetic organisms which is the site of photosynthesis

Chloroplasts contain chlorophyll, which captures sunlight for photosynthesis.

Question 3

What is Cytoplasm?

Answer 3

A jelly-like substance found in cells which contains all the organelles in the cell suspended in a liquid called the Cytosol

Cytoplasm plays a role in cellular processes and provides a medium for organelles to function.

Question 4

What does it mean to Denature a protein?

Answer 4

To alter the shape of a protein (enzyme) by breaking the bonds holding it together, rendering it unable to carry out its function

Denaturation can be caused by factors such as temperature and pH changes.

Question 5

What is the Endoplasmic Reticulum?

Answer 5

Network of membranes found throughout the cytoplasm of cells involved in processing proteins (Rough ER) and lipids (Smooth ER)

The Rough ER is studded with ribosomes, while the Smooth ER is involved in lipid synthesis.

Question 6

What is the function of the Golgi Body?

Answer 6

Network of folded/flattened membranes involved in packaging molecules like proteins for secretion

The Golgi body modifies, sorts, and packages proteins and lipids for transport.

Question 7

What is a Limiting Factor?

Answer 7

An environmental factor which is found in low supply, causing a reduction in the reaction rate of a life process

Examples include light intensity, temperature, and nutrient availability.

Question 8

What is a Lysosome?

Answer 8

Sac-like organelles which contain digestive enzymes, involved with the digestion of cellular invaders (e.g. Bacteria) and waste molecules

Lysosomes are known as the ‘clean-up crew’ of the cell.

Question 9

What are Mitochondria?

Answer 9

Organelles found in the cell’s cytoplasm which are the site of cellular respiration

Mitochondria are often referred to as the powerhouses of the cell.

Question 10

What is an Organelle?

Answer 10

An organised and specialised structure found within cells

Organelles perform specific functions essential for cell survival and function.

Question 11

What is Photosynthesis?

Answer 11

Enzyme-controlled process occurring in plants that uses energy from sunlight to fix carbon dioxide and water in the production of glucose

The overall equation for photosynthesis is 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Question 12

What is the Plasma Membrane?

Answer 12

The cell’s outer membrane which forms a double layer (bilayer) composed of phospholipids and proteins

The plasma membrane regulates what enters and leaves the cell.

Question 13

What is a Ribosome?

Answer 13

Small organelles found in the cytoplasm or on the surface of endoplasmic reticulum which are the site of protein synthesis

Ribosomes can be free-floating or bound to the rough ER.

Question 14

What is aerobic respiration?

Answer 14

Enzyme controlled process which requires oxygen to produce energy from the breakdown of glucose.

Aerobic respiration is essential for the energy metabolism in many organisms.

Question 15

What does ATP stand for?

Answer 15

Adenosine triphosphate

ATP is known as the energy carrier molecule in all living cells.

Question 16

Define a cell.

Answer 16

Basic building block/unit of life. The smallest structural and functional unit of an organism, which is typically microscopic.

Cells are the fundamental units of life and can exist as independent organisms (like bacteria) or as part of multicellular organisms.

Question 17

What is a hypotonic solution?

Answer 17

A solution with a low concentration of solute, therefore a high concentration of water

Hypotonic solutions can cause cells to swell and potentially burst.

Question 18

What does the induced fit model describe?

Answer 18

The enzyme model where the enzyme changes its shape after bonding with the substrate

This model contrasts with the lock and key model.

Question 19

What are inhibitors in the context of enzymes?

Answer 19

Poisons that bind to the active site of enzymes and stop them working

Inhibitors can be competitive or non-competitive.

Question 20

Define an isotonic solution.

Answer 20

A solution which has the same osmolarity or solute concentration as another solution

Isotonic solutions prevent net movement of water.

Question 21

What is the lock and key model?

Answer 21

The model explaining how enzymes work where the enzyme is a rigid structure

This model suggests that the substrate fits exactly into the enzyme’s active site.

Question 22

What is the matrix in the context of mitochondria?

Answer 22

Part of the mitochondria where the citric acid cycle occurs

The matrix contains enzymes and substrates for cellular respiration.

Question 23

What is mitosis?

Answer 23

The stage of the cell cycle where the replicated chromosome is split into 2 cells

Mitosis results in two genetically identical daughter cells.

Question 24

Define osmosis.

Answer 24

The net movement of water through a semi-permeable membrane from an area of high concentration to an area of low concentration

Osmosis is crucial for maintaining cell turgor.

Question 25

What is the palisade layer?

Answer 25

Part of the leaf where most chloroplasts are found, so most photosynthesis occurs here ## Footnote The palisade layer is located just below the upper epidermis of the leaf.

Question 26

What is passive transport?

Answer 26

The movement of molecules from an area of high concentration to an area of low concentration which doesn't require energy ## Footnote Examples include diffusion and facilitated diffusion.

Question 27

Define phagocytosis.

Answer 27

A form of active transport by which a cell uses its plasma membrane to engulf a large solid particle ## Footnote This process is often used by immune cells to ingest pathogens.

Question 28

What is pinocytosis?

Answer 28

A form of active transport where fluids and nutrients are ingested by cells ## Footnote Pinocytosis is often referred to as 'cell drinking.'

Question 29

What are ribosomes responsible for?

Answer 29

Part of cell where protein synthesis occurs ## Footnote Ribosomes can be free in the cytoplasm or attached to the endoplasmic reticulum.

Question 30

What occurs during the S stage of the cell cycle?

Answer 30

The stage in the cell cycle where the DNA is replicated ## Footnote The S phase is crucial for ensuring that each daughter cell receives an identical set of chromosomes.

Question 31

What does semi-conservative replication mean?

Answer 31

The name that describes the fact that the new DNA molecule being one strand new and one strand old ## Footnote This mechanism was confirmed by the Meselson-Stahl experiment.

Question 32

Define a semi-permeable membrane.

Answer 32

A membrane that allows some substances to pass through it but not others ## Footnote Semi-permeable membranes are essential for processes like osmosis.

Question 33

What is the stroma in chloroplasts?

Answer 33

Part of chloroplast where the dark stage occurs ## Footnote The stroma contains enzymes and substrates needed for the Calvin cycle.

Question 34

What does turgid mean in cellular biology?

Answer 34

A cell that is swollen, bloated, puffed up or inflated ## Footnote Turgidity is important for maintaining plant structure and health.

Question 35

What is the active site?

Answer 35

A specific shaped part of an enzyme where the substrate fits ## Footnote Active sites are crucial for enzyme functionality.

Question 36

Define active transport

Answer 36

The movement of molecules from an area of low concentration to an area of high which requires energy ## Footnote Active transport is essential for maintaining cellular homeostasis.

Question 37

What is aerobic respiration?

Answer 37

Respiration in the presence of oxygen ## Footnote Aerobic respiration is more efficient than anaerobic respiration.

Question 38

What is an anabolic enzyme?

Answer 38

An enzyme that takes small molecules and joins them together ## Footnote Anabolic processes are involved in building complex molecules.

Question 39

What is anaerobic respiration?

Answer 39

Respiration with limited oxygen ## Footnote Anaerobic respiration occurs in environments lacking oxygen.

Question 40

What is a catabolic enzyme?

Answer 40

An enzyme which takes large molecules and breaks them up ## Footnote Catabolic enzymes are important for digestion and metabolism.

Question 41

What is the cell wall?

Answer 41

Rigid layer of cells found only in plants ## Footnote The cell wall provides structural support and protection.

Question 42

What is chlorophyll?

Answer 42

Pigment found in plants which gives the plant its green colour ## Footnote Chlorophyll plays a key role in photosynthesis.

Question 43

What are cristae?

Answer 43

Part of mitochondria (the folds) where the electron transfer chain occurs ## Footnote Cristae increase the surface area for biochemical reactions.

Question 44

What does it mean to denature an enzyme?

Answer 44

The changing in the shape of the active site of an enzyme, so the substrate can no longer fit - caused by high temperatures and incorrect pH ## Footnote Denaturation can lead to loss of enzyme activity.

Question 45

What is the full name for DNA?

Answer 45

Deoxyribose nucleic acid ## Footnote DNA is the hereditary material in organisms.

Question 46

Define diffusion

Answer 46

The movement of materials from an area of high concentration to an area of low concentration ## Footnote Diffusion is a passive transport mechanism.

Question 47

What is DNA replication?

Answer 47

The copying of DNA before the cell divides ## Footnote Accurate DNA replication is essential for cell division.

Question 48

What are enzymes?

Answer 48

Biological catalysts which speed up biochemical reactions in an organism ## Footnote Enzymes lower the activation energy required for reactions.

Question 49

What is facilitated diffusion?

Answer 49

A form of passive transport where molecules move across the cell membrane through the membrane proteins ## Footnote Facilitated diffusion is important for the transport of large or polar molecules.

Question 50

What does flaccid mean in cellular terms?

Answer 50

A cell that is limp and floppy ## Footnote Flaccidity can result from loss of water in plant cells.

Question 51

What occurs in the G1 phase of the cell cycle?

Answer 51

The stage in the cell cycle where the cell grows and does its job ## Footnote G1 is critical for cellular growth and function.

Question 52

What occurs in the G2 phase of the cell cycle?

Answer 52

The stage in the cell cycle where the replicated chromosomes are checked for mistakes ## Footnote G2 ensures that DNA is accurately copied before mitosis.

Question 53

What is the Golgi body?

Answer 53

Part of a cell where proteins are modified and packaged ## Footnote The Golgi body is essential for processing and transporting proteins.

Question 54

What are grana?

Answer 54

Part of chloroplast where the light stage occurs ## Footnote Grana are stacked structures that contain chlorophyll.

Question 55

What is a hypertonic solution?

Answer 55

A solution with a high concentration of solute, therefore a low concentration of water ## Footnote Cells in a hypertonic solution may lose water and shrink.