Lecture 1

Question 1

What is the study of tissues, cells and subcellular components in a biological context?

Answer 1

Microscopy

Question 2

What is the isolation of subcellular organelles and the components that make them up?

Answer 2

Centrifugation Chromatography.

Question 3

What are two ways of analysing biological macromolecules such as proteins and DNA?

Answer 3

Gel electrophoresis

Mass-spectrometry

Question 4

What is the smallest unit of life?

Answer 4

Cells.

Question 5

What are bacteriophages?

Answer 5

Small viruses that infect & kill bacteria

Question 6

What are the model cell systems for:
A) Prokaryotes
B) Lower Eukaryotes
C) Higher Eukaryotes

Answer 6

A) E.Coli
B)yeast - S. cerevisiae
C)Human tissue culture cells - HeLa cells

Question 7

Describe the different properties expressed by fibroblasts, muscle cells and epithelial cells.

Answer 7

Many cultured mammalian cells show differentiated properties that reflect their origin: fibroblast secrete collagen; muscle cells fuse to form muscle fibres and epithelial cells join to form large sheet.

Question 8

Zebrafish are useful for the study of what?

Answer 8

Vertebrate development

Question 9

Drosphophila melogaster are useful for the study of what?

Answer 9

(fruit fly)- classical genetics

Question 10

Caenorhabditis elegans are useful for the study of what?

Answer 10

(nematode worm) genome sequencing

Question 11

What is the role of Peroxisomes?

Answer 11

Peroxisomes break down fatty acids, alcohol & toxins. Defects in making new peroxisomes can lead to diseases such as Zellweger syndrome = imbalance in lipid metabolism

Question 12

What is the role of the cytosol?

Answer 12

Typically largest single compartment in the cell and site of many fundamental cellular processes:

• Protein synthesis & degradation
• Intermediary metabolism

Question 13

What is the role of the nucleus?

Answer 13

• Information store
• Surrounded by nuclear envelope = double membrane
• Contains cellular DNA as chromosomes
• Ribosomal RNA transcribed & ribosomal subunits are assembled

Question 14

What is the role of the chromosomes?

Answer 14

Chromosome structure changes during the cell cycle when they undergo condensation & decondensation
-Progress towards cell division

Question 15

What is the role of the mitochondria?

Answer 15

-Inner membrane extensively folded – increased surface area for cellular respiration
-Site of oxidative phosphorylation
Generate ATP = “energy”
-Mitochondria can form complex networks in the cell

Question 16

What is the role of the chloroplasts?

Answer 16

-In Plants & Algae

Site of photosynthesis = harvesting energy from sunlight.

Question 17

What is the role of endoplasmic reticulum?

Answer 17

-Irregular maze of interconnected spaces enclosed by a single membrane. Entry point to secretory pathway
-Makes: secretory & membrane proteins + lipids
-Rough endoplasmic reticulum bound to ribosomes
-smooth ER- abundant in human cells active in lipid metabolism and in liver for detoxification of lipid soluble compounds
Sarcoplasmic reticulum-ER derived Ca2+ store in muscle cells: important role during muscle contraction

Question 18

What is the role of the Golgi?

Answer 18

• Appearance of flattened sacs/discs
• Receives proteins and lipids as cargo from ER
• Cargo transits Golgi to plasma membrane
• Modification of cargo e.g. glycosylation & sorting of cargo to correct location

Question 19

What is the endomembrane composed of?

Answer 19

Nuclear envelope, ER and Golgi thought to have evolved from plasma membrane = all part of so called endomembrane.

Question 20

Most synthesis occurs in the..

Answer 20

-cytosol

Question 21

What is the cytoskeleton composed of?

Answer 21

-Protein filaments such as Actin filament, Microtubules, filaments and Intermediate filaments
-often anchored to the plasma membrane
-Enable directed movement
-Actin- thinnest: movement
-Intermediate filaments: mechanical strength
-Microtubules- thickest: chromosome segregation
(during cell division)

Question 22

What is cystic fibrosis most commonly caused by?

Answer 22

• most commonly caused by a defect in protein trafficking

- the channel protein is made but it is not delivered to the correct subcellular location.

Question 23

What is a key factor that causes Alzheimers disease?

Answer 23

• an imbalance in protein processing is one key element

- Results in toxic protein aggregates

Question 24

Describe what causes tumour formations/cancer

Answer 24

-Uncontrolled cell division
-Invasive character - grow
in the wrong place
-Mutations in the Ras protein prevent it being turned off leading to uncontrolled cell proliferation. 30% of human cancers contain such activating mutations in a Ras gene.