Lectures 1 & 2

Question 1

What is meant by health?

Answer 1

a state of complete physical, mental and social well-being

Question 2

What is meant by disease?

Answer 2

any deviation from the normal structural or functional health state of an individual

Question 3

What is meant by patient?

Answer 3

individuals who seek medical care, treatment, or attention from healthcare professionals, including pharmacists, due to a disease, condition, injury, or a health-related concern.”

Question 4

What are the features of a red blood cell?

Answer 4

*Biconcave shape
* No nucleus
* Contain haemoglobin
* Small and flexible

Question 5

What are the features of neurons?

Answer 5

• Thin and long cells
• Branched at their ends
• Different subcellular parts
• Release of neurotransmitter signals

Question 6

What are the levels of organisation in the human body?

Answer 6

he levels of increasing complexity are: Cell → Tissue → Organ → Organ System → Organism

Question 7

What are the two main types of cells?

Answer 7

Prokaryotic cells (bacteria) and eukaryotic cells (e.g. human cells). Prokaryotic cells lack a nucleus and organelles, while eukaryotic cells have a nucleus and membrane-enclosed organelles

Question 8

What are the four major organic macromolecules in cells?

Answer 8

Carbohydrates/polysaccharides, proteins, lipids, and nucleic acids. These are polymers made of specific repeating molecular units called monomers

Question 9

What are the basic components found in all cells?

Answer 9

Plasma membrane, cytosol, ribosomes, genome (DNA), and biological macromolecules

Question 10

What is anabolism?

Answer 10

Cells link monomers together to form a polymer
through polymerisation/condensation reactions
(requiring energy)

Question 11

What is catabolism?

Answer 11

Polymers are broken down into smaller molecules
by hydrolysis (realising energy)

Question 12

what is metabolism?

Answer 12

catabolism + anabolism reactions

Question 13

What does the cytoplasm do In prokaryotes?

Answer 13

Internal content of the cell - site of many reactions

Question 14

Ribosome function in prokaryotes?

Answer 14

▪ Composed of a large (50S) and a small subunit (30S)
▪ Each subunit is made of rRNA and proteins
▪ Involved in protein synthesis, translating mRNA code

Question 15

Bacterial DNA chromosome in prokaryotes?

Answer 15

▪ Dispersed in a central cytoplasmic space - Nucleoid
▪ Single circular DNA - not linked to histone proteins

Question 16

Inclusion bodies in prokaryotes?

Answer 16

 Aggregates of reserve material (Storing function)

Question 17

Plasmids in Prokaryotes?

Answer 17

Confer new ability, such as degradative ability of antibiotics = drug resistance

Question 18

Plasma membrane in prokaryotes? (internal surface layer)

Answer 18

Flexible lipid bilayer, as in eukaryotic cells (with no sterols).
 Controls the movement of molecules (nutrients/waste)
 sometimes, site of reactions (respiration/photosynthesis

Question 19

Cell wall in prokaryotes?(middle surface layer)

Answer 19

 Rigid structure to preserve cell shape & integrity

Question 20

Glycocalyx in prokaryotes? (outer surface layer)

Answer 20

Polysaccharides layer: Capsule (organised and stable) or Slime layer (loosely attached)
 Protection against dehydration, immune system (phagocytosis) and antibiotics
 Adherence factor

Question 21

Flagellum in prokaryotes?

Answer 21

 Long and whip-like appendages
 Used for cell motility (movement).
 It is also a sensory structure to detect nutrients

Question 22

Fimbria/Pili in prokaryotes?

Answer 22

 Short and thin projections
 Used for attachment to a surface or other cells

Question 23

Sex pili in prokaryotes?

Answer 23

 Rigid hair-like tubular structures (longer than fimbriae)
 Use to facilitate genetic material transfer between two bacteria (through the conjugation
process)

Question 24

Cytoplasm in Eukaryotes?

Answer 24

Content inside the plasma membrane (covered in Lec. 7) excluding the nucleus
* Highly organised and dynamic
* It includes:
 cytosol
* gel-like fluid (pH 7.2) to support organelles
* It includes ribosomes, cytoskeleton, enzymes, etc
* It is the site of many cellular activities:
 Protein synthesis (Lec. 4) and degradation
 Metabolic reactions (e.g. glycolysis)
 Cell signalling pathways (Lec. 8)
 distinct cell organelles
* enclosed by membranes (separated by the cytosol)

Question 25

Ribsosomes in eukaryotic cells?

Answer 25

Function: Cell machinery for protein synthesis (translation step – Lec. 4)
Structure:
* Made by 2 subunits: large (60S) & small (40S)  forming 80S
 bigger than the prokaryotic ones (50s and 30S  70S)
Types: Free floating in the cytosol or bound to the rough endoplasmic reticulum
 Both subunits are combinations of :
 Ribosomal proteins +
 ribosomal RNA (rRNAs)
S refers to their sedimentation coefficients (indirect size measure)

Question 26

Cytoskeleton in Eukaryotes?

Answer 26

A network of protein filaments and tubules that provides structural support

Functions:

 Structural support: cell shape & resists mechanical stress
 Intracellular transport: facilitates movement of
organelles, vesicles, and molecules
 Regulates cellular processes (eg cell division & motality

Structures - Composition
* 3 types of filamentous protein polymers (long repetitions of 1 or more proteins):
Microfilaments (7 nm in diameter),
Intermediate filaments (10 nm in diameter)
Microtubules (25 nm in diameter)

Question 27

What is the structure and major functions of microfilaments in the cytoskeleton?

Answer 27

STRUCTURE:
* Long, thread-like filaments of 2 helical strands of actin
protein repetitions - (7nm in ⌀)
MAJOR FUNCTIONS:
Depending on interaction with actin binding proteins (e.g. myosin).
Very dynamic- Rapid assembly and disassembly for quick rearrangements
 Muscle contraction
 Assist with cell movement
 Support cell’s shape (e.g. microvilli in intestinal cells)
 Cell division: formation of contractile ring in cytokinesis

Question 28

What is the structure and functions of the cytoskeletons intermediate filaments?

Answer 28

STRUCTURE
* Rope-like fibres formed by many long strands of several
types of proteins (e.g. keratin) twisted together - (10nm in ⌀)

MAJOR FUNCTIONS
 Provide mechanical strength and stability to cells and
tissues (abundant in muscle cells)
 Anchor cells in extracellular matrix
No effect in cell motility (not bound to motor proteins). More stable

Question 29

What is the structure and functions of the cytoskeletons microtubules?

Answer 29

STRUCTURE
* Long and rigid hollow cylinders made by repetitions of two
tubulin protein subunits (α & β) - (25nm in ⌀)

MAJOR FUNCTIONS
 Cell structural support
 Intracellular transport (linked to motor proteins, e.g. kinesin, dynein)
 Generate force and cell movement (cilia and flagella)
 Cell divisions  forming Centrioles  DNA segregation

Question 30

What can cytoskeleton defects lead to?

Answer 30

Cytoskeleton defects can lead to cardiomyopathies, cancer, etc.
* Some anti-cancer drugs interfere with microtubule formation to block
the uncontrolled cancer cell divisions.