full topic 2

Question 1

What are the key features of a eukaryotic cell?

Answer 1

Membrane-bound organelles and DNA enclosed in a nucleus.

Question 2

What is the function of the nucleus?

Answer 2

Stores DNA, site of transcription, and makes ribosomes.

Question 3

What is the function of ribosomes?

Answer 3

Site of protein synthesis.

Question 4

Function of rough ER?

Answer 4

Processes and transports proteins.

Question 5

Function of smooth ER?

Answer 5

Synthesises and processes lipids.

Question 6

Function of the Golgi apparatus?

Answer 6

Modifies and packages proteins and lipids; forms lysosomes.

Question 7

Function of mitochondria?

Answer 7

Site of aerobic respiration and ATP production.

Question 8

Function of chloroplasts?

Answer 8

Absorbs light for photosynthesis.

Question 9

Function of the cell wall?

Answer 9

Provides structural support and prevents osmotic bursting.

Question 10

Function of the vacuole?

Answer 10

Maintains turgor pressure and stores chemicals.

Question 11

What is a tissue?

Answer 11

Group of similar cells working together to perform a function.

Question 12

What is an organ?

Answer 12

Structure formed of tissues that performs a specific function.

Question 13

What is an organ system?

Answer 13

Group of organs working together for a function.

Question 14

How do organelles relate to cell function?

Answer 14

Cells have more of the organelles they need for their specific role.

Question 15

How do prokaryotic cells differ from eukaryotic cells?

Answer 15

No membrane-bound organelles; DNA is free in cytoplasm.

Question 16

What structures are found in prokaryotes but not eukaryotes?

Answer 16

Plasmids, capsule, circular DNA.

Question 17

What is the structure of a virus?

Answer 17

Nucleic acid in a protein coat (capsid), sometimes with a lipid envelope.

Question 18

Why are viruses considered non-living?

Answer 18

No metabolism, cannot reproduce without a host.

Question 19

Define magnification.

Answer 19

How many times larger the image is than the actual object.

Question 20

Define resolution.

Answer 20

Minimum distance at which two objects can be distinguished.

Question 21

How does a TEM work?

Answer 21

Electrons pass through thin specimen; image formed based on electron absorption.

Question 22

How does an SEM work?

Answer 22

Electrons bounce off specimen; produces a 3D image.

Question 23

Why can electron microscopes resolve smaller structures?

Answer 23

They use electrons with shorter wavelengths than light.

Question 24

Why use cold buffer

Answer 24

isotonic

Question 25

What is ultracentrifugation?

Answer 25

Spinning homogenised cells at different speeds to separate organelles by density.

Question 26

Order of organelle separation in centrifugation?

Answer 26

Nucleus → chloroplasts/mitochondria → lysosomes → ER → ribosomes.

Question 27

What are the stages of the cell cycle?

Answer 27

Interphase, mitosis, cytokinesis.

Question 28

What happens in interphase?

Answer 28

DNA replicates; organelles and cytoplasm increase.

Question 29

What happens in prophase?

Answer 29

Chromosomes condense; spindle forms; nuclear envelope breaks down.

Question 30

What happens in metaphase?

Answer 30

Chromosomes align along equator and attach to spindle.

Question 31

What happens in anaphase?

Answer 31

Sister chromatids pulled to opposite poles.

Question 32

What happens in telophase?

Answer 32

Chromosomes decondense; nuclear envelope reforms.

Question 33

Why is mitosis important?

Answer 33

Growth, repair, and asexual reproduction.

Question 34

How can uncontrolled cell division lead to cancer?

Answer 34

Mutations in DNA lead to loss of control in cell cycle.

Question 35

How do cancer drugs target mitosis?

Answer 35

Disrupt spindle formation or DNA replication.

Question 36

How do prokaryotes replicate?

Answer 36

Binary fission: replicate DNA and divide.

Question 37

How do viruses replicate?

Answer 37

Attach to host, inject genetic material, hijack machinery to make viral particles.

Question 38

How do you prepare a root tip squash?

Answer 38

Cut root tip, treat with acid, stain, squash under coverslip.

Question 39

Why stain root tip cells?

Answer 39

To make chromosomes visible.

Question 40

What is the mitotic index?

Answer 40

Proportion of cells undergoing mitosis.

Question 41

How to calculate mitotic index?

Answer 41

Mitotic index = (cells in mitosis) / (total cells).

Question 42

What is the fluid mosaic model?

Answer 42

Membrane made of phospholipid bilayer with proteins scattered throughout.

Question 43

What does cholesterol do in membranes?

Answer 43

Reduces fluidity and permeability.

Question 44

What is simple diffusion?

Answer 44

Passive movement of small, non-polar molecules down concentration gradient.

Question 45

What is facilitated diffusion?

Answer 45

Passive transport using channel or carrier proteins.

Question 46

What is osmosis?

Answer 46

Movement of water from high to low water potential through a partially permeable membrane.

Question 47

What is active transport?

Answer 47

Transport against concentration gradient using ATP and carrier proteins.

Question 48

What is co-transport?

Answer 48

Transport of one substance with another, e.g., Na+ with glucose.

Question 49

How to find water potential of plant tissue?

Answer 49

Place in sucrose solutions, measure % mass change, use calibration curve.

Question 50

Why does mass change in osmosis?

Answer 50

Water enters/leaves cells depending on water potential gradient.

Question 51

How to test effect of temperature on membrane permeability?

Answer 51

Use beetroot cubes, measure pigment leakage via colorimeter.

Question 52

Why does high temperature increase permeability?

Answer 52

Denatures membrane proteins and disrupts phospholipid bilayer.

Question 53

What is an antigen?

Answer 53

A molecule that triggers an immune response.

Question 54

What is phagocytosis?

Answer 54

Engulfing and digesting pathogens by phagocytes.

Question 55

What are T lymphocytes?

Answer 55

Cells that respond to antigens on Antigen Presenting Cells; stimulate other immune cells.

Question 56

What are B lymphocytes?

Answer 56

Produce specific antibodies after clonal selection and expansion.

Question 57

What are antibodies?

Answer 57

Proteins that bind specifically to antigens.

Question 58

What is the primary immune response?

Answer 58

First exposure, slow antibody production.

Question 59

What is the secondary immune response?

Answer 59

Faster, stronger response due to memory cells.

Question 60

How do vaccines work?

Answer 60

Introduce antigens to stimulate memory cell production.

Question 61

What is herd immunity?

Answer 61

Protection when enough people are vaccinated to prevent spread.

Question 62

What is passive immunity?

Answer 62

Receiving antibodies from another organism (e.g., breast milk).

Question 63

What is active immunity?

Answer 63

Immunity from your own immune response.

Question 64

What are monoclonal antibodies?

Answer 64

Identical antibodies from cloned B cells.

Question 65

How are monoclonal antibodies used?

Answer 65

Target drugs to cells, medical diagnosis (e.g., ELISA).

Question 66

What is an ELISA test?

Answer 66

Uses antibodies and enzymes to detect antigens or antibodies.

Question 67

What does a color change in ELISA indicate?

Answer 67

Presence of target antigen or antibody.

Question 68

What does HIV infect?

Answer 68

Helper T cells.

Question 69

How does HIV cause AIDS?

Answer 69

Kills helper T cells; weakens immune system.

Question 70

Why don't antibiotics work on viruses?

Answer 70

Viruses don't have cell walls or metabolic pathways.