1What is the main focus of biomolecules?
How structure determines function
2Why is biomolecule structure important?
Because shape determines biological activity
3What key roles do biomolecules have in cells?
Cell signalling, structural support, and genetic information
4What type of molecule is a phospholipid?
An amphipathic lipid
5What does amphipathic mean?
Having both hydrophilic and hydrophobic regions
6What are the parts of a phospholipid molecule?
A hydrophilic head and hydrophobic fatty acid tails
7What structure do phospholipids form in water?
A phospholipid bilayer
8Why do phospholipids form bilayers?
Hydrophilic heads face water while hydrophobic tails avoid water
9What is the cell membrane?
A phospholipid bilayer with embedded proteins
10What is the function of cholesterol in cell membranes?
Regulates membrane fluidity
11What are glycolipids?
Lipids with carbohydrate chains attached
12What are glycoproteins?
Proteins with carbohydrate chains attached
13What is the role of membrane carbohydrates?
Cell recognition and cell signalling
14What are integral membrane proteins?
Proteins embedded in the membrane (often spanning the bilayer)
15What are peripheral membrane proteins?
Proteins loosely attached to the membrane surface
16What are channel proteins?
Membrane proteins that allow specific substances to pass through
17What is one function of the membrane as a boundary?
Defines the cell as a separate entity
18How does the membrane act as a barrier?
Controls what enters and leaves the cell
19How does the membrane support cell identification?
Allows immune system to distinguish self from non-self
20What role does the membrane play in signalling?
Contains receptors for communication
21What is the cytoskeleton?
A dynamic network of protein filaments
22What are cytoskeleton functions?
Cell movement, structure, stability, and organisation
23What are the three cytoskeleton components?
Actin filaments, microtubules, and intermediate filaments
24What are actin filaments made of?
Two strands of actin protein twisted together
25How do actin filaments usually occur in cells?
In bundles
26What role does actin play in cell movement?
Forms pseudopodia
27What role does actin play in cell division?
Forms a contractile ring during cytokinesis
28What are microtubules composed of?
Tubulin protein subunits
29What is the basic shape of microtubules?
A hollow tube
30What are main functions of microtubules?
Structural support, intracellular transport tracks, and chromosome movement
31What role do microtubules play in cell division?
Form the mitotic spindle and move chromosomes
32What role do microtubules play in cilia and flagella?
Form the structural framework
33What are intermediate filaments made of?
Overlapping staggered tetramers of protein
34What is the approximate diameter of intermediate filaments?
8–12 nm
35What is the main function of intermediate filaments?
Bear tension and reinforce cell shape
36How stable are intermediate filaments compared with actin/microtubules?
More stable and permanent
37What proteins commonly form intermediate filaments?
Keratins
38What are the two largest keratin groups?
Type I and Type II keratins
39What are lamins?
Intermediate filament proteins important for nuclear structure
40What disorder can result from mutations in keratin genes K5 or K14?
Epidermolysis bullosa simplex
41What is the extracellular matrix (ECM)?
A network of proteins and polysaccharides outside cells
42What macromolecules make up the ECM?
Proteins and polysaccharides
43What structure do ECM proteins form?
Large fibres
44What property do ECM polysaccharides provide?
Gel-like character
45What are the major roles of the ECM?
Structural support, tissue organisation, and cell signalling
46What is ATP?
The main energy currency of the cell
47What does ATP provide for cellular processes?
Energy
48What are information molecules in cells?
DNA and RNA
49What is the function of DNA?
Stores genetic information
50What type of backbone does DNA have?
Sugar-phosphate backbone
51What bases are found in DNA?
Adenine, thymine, cytosine, and guanine
52What are purines?
Adenine and guanine
53What are pyrimidines?
Cytosine and thymine
54What is RNA?
A nucleic acid involved in gene expression
55What is the function of mRNA?
Encodes proteins
56What is the function of tRNA?
Adaptor between mRNA and amino acids
57What is the function of rRNA?
Forms the ribosome
58What is passive transport?
Movement from high concentration to low concentration
59What substances can cross by passive diffusion?
Gases, steroid hormones, and fatty acids
60What is facilitated transport?
Transport using carrier proteins or ion channels
61What substances commonly use facilitated transport?
Glucose, amino acids, and ions
62What is active transport?
Movement from low concentration to high concentration
63What does active transport require?
Energy from ATP
64What proteins are required for active transport?
Highly selective carrier proteins
65What is a uniporter?
A carrier that moves one type of molecule
66What is a symporter?
A carrier that moves two substances in the same direction
67What is an antiporter?
A carrier that moves two substances in opposite directions
68What ions are moved by the sodium-potassium pump?
3 Na⁺ out and 2 K⁺ into the cell
69What does the sodium-potassium pump require?
ATP
70Why is the sodium-potassium pump important?
Maintains ion gradients across membranes
71What is endocytosis?
Transport of substances into the cell using vesicles
72What is phagocytosis?
Endocytosis of large particles
73What is pinocytosis?
Endocytosis of extracellular fluid
74What is exocytosis?
Release of substances from the cell when vesicles fuse with the membrane
75What proteins move organelles along microtubules?
Motor proteins
76Which motor proteins are involved in intracellular transport?
Kinesin and dynein
77How do kinesin and dynein move relative to each other?
In opposite directions
78What role do microtubules play in organelle transport?
Provide tracks for motor proteins
79What structure do cilia and flagella share?
9 pairs of microtubules around 2 central microtubules
80What motor protein drives bending of cilia and flagella?
Dynein
81What function do anchored cilia perform?
Move fluid across the cell surface
82Give an example of cilia function in humans
Sweeping mucus from the lungs
83What structure organises microtubules in animal cells?
The centrosome
84What structures make up the centrosome?
A pair of centrioles
85How are microtubules arranged in centrioles?
Nine triplets arranged in a ring
86What role do centrioles play in cell division?
Organise the mitotic spindle