Intro to Cell Biology

Question 1

Light Microscope

Answer 1

• Up to 1000X bigger
• Resolve as low as 0.2μm
• Specimen must be prepared to allow light to pass through it

Question 2

Fluorescent Microscope

Answer 2

• Fluorescence microscopy
  makes use of fluorophores –
  special dyes
• These dyes are ‘excited’ by
  one wavelength and ’emit’ at
  a higher wave length

Question 3

TEM

Answer 3

• Same principle as light but uses beam of
  electrons rather than light.
• Specimen fixed and plastic embedded
• Stained with salts of uranium and lead

Question 4

SEM

Answer 4

• Specimen coated in thin film of heavy
  metals
• Electrons scattered or emitted as electrons
  bombard surface of specimen
• Creates 3D images – detail between 3nm
  and 20nm

Question 5

Function of a microscope

Answer 5

Magnifies a specimen.
* LM = X40 – X1000
* EM = X1000 – x 1,000,000
* Illuminates a specimen.
* Light or Electrons are focussed through (or on to)
a specimen by a series of condenser lenses

Question 6

Resolution

Answer 6

effective distance two
points/objects must be apart before they are
perceived as being separate objects.

Question 7

Original Cell Theory

Answer 7

All organisms are composed of one or more cells
(Schleiden & Schwann 1838-39).
* The cell is the basic unit of life in all living things
(Schleiden & Schwann 1838-39).
* All cells are produced by division of pre-existing
cells (Virchow 1858)

Question 8

Modern Cell Theory

Answer 8

-Cells contain hereditary information (DNA) which is passed onto cells via cell division
-Cells are basically the same in chemical composition and metabolic activities
-All basic chemical and physiological functions are carried out inside cells e.g. digestion

Question 9

cells

Answer 9

self-replicating structures that are
capable of responding to changes in their
environment

Question 10

Prokaryotes

Answer 10

simplest forms of cells.
* Bacteria and Archea
do not have
membrane bound organelles or a cytoskeleton. DNA
is restricted to a region called the nucleoid

Question 11

Eukaryotes

Answer 11

complex cells capable of
forming multicellular organisms.
* Plants, animals and fungi
DNA is contained in a membrane bound nucleus. A
cytoskeleton, and membrane bound organelles
such as mitochondria, occur within the cytoplasm.

Question 12

Responding to changes in environment

Answer 12

Maintenance of the internal
environment
 Sensing the external
environment
 Controlling the flow of
molecules into and out of the
cell
 Catalyzing chemical reactions
 Generating useful energy
 Accessing genetic information
 Synthesis of biological
molecules
 Regulating information flow

Question 13

Eukaryotic compartmentalisation

Answer 13

Internal membranes result in a
number of different compartments
(organelles).
Helps regulate local conditions e.g.
PH.
Compartmentalisation allows
different activities to be carried out in
different parts of the cell.

Question 14

Organelles

Answer 14

structures that are
surrounded by at least one distinct
membrane:

Question 15

Nucleus

Answer 15

• DNA housed in nucleus as
  chromatin (Mass of DNA
  and proteins)
• Genome
• Nuclear envelope - nucleus
  has a double membrane
  with nuclear pores to allow
  substances to pass to/from
  the cytoplasm
• Within the nucleus, in the
  nucleolus (a sub-organelle):
  rRNA and proteins are
  assembled to form
  ribosomes
• Ribosomes are the
  machinery for protein synthesis

Question 16

Mitochondria

Answer 16

 Double membrane.
 Folds of inner membrane
forms cristae.
 Energy rich molecules
such as glucose  ATP
synthesis

Question 17

The rough and smooth Endoplasmic
Reticulum

Answer 17

Outer layer of nuclear
envelope continues into
ER
* Maze of membrane
enclosed, interconnected
spaces – ER lumen
* Expand to form cisternae
Relationship between nuclear envelope and ER.
RER (rough): Protein synthesis, Post-
translational modification
- SER (smooth): Phospholipid
synthesis, Calcium storage, Glucose
formation, Toxin removal

Question 18

Golgi

Answer 18

Cis, medial and trans
- Glycosylation (add carb),
Phosphorylation (add phosphate)
Proteolysis (break down)
- Trans –buds off to form ‘transport
vesicles

Question 19

Vesicles

Answer 19

 Membrane trafficking – movement of cargo-
containing vesicles between organelles
(ERGolgi)
 Exocytic: From inside the cell to the outside.
 Endocytic: From outside into the cell

Question 20

peroxisome

Answer 20

Small membrane enclosed
organelle contain at least 50
enzymes
 Oxidizes molecules (long chain
fatty acids) and generates
hydrogen peroxide (H2O2) as a
byproduct
 Contain an enzyme called catalase
that efficiently degrades hydrogen
peroxide into water and molecular
oxygen
 Can also oxidize toxic chemicals
amongst many other functions

Question 21

Chloroplast

Answer 21

 Double membrane.
 Stacks of thylakoid membranes
forming structures called
grana.
 Contains chlorophyll
 Use light energy to create the
carbon polymers for
macromolecules (Autotrophs).
 Plant cells then extract stored
energy, by oxidizing these
sugars in their mitochondria

Question 22

Tissue Types

Answer 22

1)epithelial tissue
2) connective tissue
3) muscle tissue
4) nervous tissue
* Combinations of tissues that work closely
together are called organs e.g. lungs, heart, liver,
brain, intestines

Question 23

Diseases and Tissue structure and Function

Answer 23

Diseases often diagnosed
when they begin to affect
cells:
 Cancer
 Heart diseases
 Leads to cell/tissue
dysfunction/death
 Early detection: biomarkers

Question 24

Biofilms

Answer 24

 ‘Aggregate’ of microorganisms
 Embedded within a self-produced matrix of extracellular
polymeric substance
 Can be adapted to environmental conditions by its
inhabitants