Cell organelles

Question 1

Cell discovery key people

Answer 1

• Robert Hooke: used simple compound microscope to observe thin slices of cork (cell biology) and saw box-like structures
• Antonie van Leeuwenhoek: perfected the design of the simple microscope = 200-300x magnification

Question 2

Cell theory key people

Answer 2

• Theodore Schwann and Matthias Schleiden:
  1. All living organisms are composed of one or more cells.
  2. The cell is the basic unit of structure and organisation in organisms.
• Rudolf Virchow (Robert Remak):
  3. Cells arise from pre-existing cells.

Question 3

Common features of cells

Answer 3

• bound by a plasma membrane
• have chromosomes carrying genes made from DNA
• have ribosomes that make the proteins according to the information in
  the genes

Question 4

Cytoplasm

Answer 4

entire region between the cell membrane and the nucleus that houses DNA (cytosol + organelles)

Question 5

Plasma membrane

Answer 5

• keeps the cell together
• separates living cell from non-living surroundings
• not solid, has tiny openings that let things in and out
• exhibits selective permeability, allowing some substances to cross more readily
  than others

Question 6

Name the 2 main cell types

Answer 6

• Prokaryotic
• Eukaryotic

Question 7

Prokaryotic cells

Answer 7

• unicellular organisms
• less organised
• DNA is not separated by a membrane
• lack of more complex structures

Question 8

Eukaryotic cells

Answer 8

• multicellular organisms
• more organised
• subdivided by internal membranes
  into compartments

Question 9

Plasma membrane structure

Answer 9

• fundamental unit of biological membranes = asymmetric phospholipid bilayer
• Other lipids scattered between phospholipid molecules
• Proteins are embedded and otherwise attached
• Carbohydrates (oligosaccharides, glycans) exist on the outer surface

Question 10

Phospholipids

Answer 10

• amphipathic lipid molecules
• contain a polar end (hydrophilic) and a non-polar end (hydrophobic)
• non-polar end: tails of long hydrocarbon chains - fatty acids
• polar head group: phosphoric acid conjugated to a base (choline,
  serine, ethanolamine, inositol)
• linker molecule = glycerol, a three carbon molecule

Question 11

Phospholipid bilayer

Answer 11

• flat sheet containing 2 layers of phospholipids
• hydrophobic tails attracted to each other → provide separation
• exposes the hydrophilic heads to the external and internal water soluble environments → allow mixing with the environment

Question 12

Name the 2 types of membrane proteins

Answer 12

1. Integral proteins
2. Peripheral proteins

Question 13

Organelle

Answer 13

• Intracellular compartment that carries out a specific function within the cell
• All organelle come from mother

Question 14

Examples of membraneous organelles

Answer 14

• nucleus
• rough endoplasmic reticulum
• smooth endoplasmic reticulum
• mitochondria
• Golgi apparatus
• lysosomes
• peroxisomes

Question 15

Non-membraneous organelles

Answer 15

• ribosomes
• cytoskeletal structures
• condensed protein structures