Group 2

Question 1

Cells are made up of:

Answer 1

1) Information: All cells possess DNA, the hereditary material of genes, and RNA, which
provides the information necessary to build various proteins

2) Chemistry: Oparin’s (1924) and Haldane’s (1929) primordial soup hypothesis:
- putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors
Pre-biotic chemistry:
Chemical experiment that simulated the conditions thought to exist on the early Earth and to test the chemical origin of life under those conditions.

3) Compartments:
- Usually defined by single or double lipid layer membrane.
- Examples of cellular compartments include mitochondria, chloroplasts, the cell nucleus, vesicles, endoplasmic reticulum
- Establish physical boundaries
that enable the cell to carry out different metabolic activities.
* Generate a micro- environment to spatially and temporally regulate biological
processes.

Question 2

Prokaryote Vs Eukaryote

Answer 2

Prokaryotes: bacteria/archaea
-single cell , 1-10 micrometers
-no nucleus/organelles
-small or no ribosomes
-Asexual reproduction
-DNA in nucleoid

Eukaryotes: plant, animal and fungi
-multi cellular, 10-100 micrometers
-nucleus/organelles
-large ribosomes
-DNA in nucleus compartments in chromosomes

Question 3

Differences in Plant Vs Animal Cells

Answer 3

Plant:
-cell wall
-vacuole
-chloroplasts

Animal:
-Lysosomes
-Microvilli

Question 4

Membrane Fluidity

Answer 4

Can be regulated with temperature:
-warming = more fluid (creates liquid crystals)
-cooling = less fluid (crystalline gel)

Can be determined by the types of lipids in membranes:
-saturated (less fluid - strict)
-unsaturated (more fluid - strict)

Membrane must be fluid, so to respond to temp changes, membranes can:
-desaturate lipids
-exchange lipid chains
-add cholesterol to alter flexibility of lipids
- add cholesterol to liquid crystal = less fluid
- add cholesterol to gel membrane = more fluid

Question 5

Membrane Proteins

Answer 5

1) Integral: membranes proteins span the lipid bilayer
-transport nutrients and ions
-cell-cell communication (gap junction)
-attachment
2) peripheral: membrane proteins associate with the surfaces of the lipid bilayer
3) Lipid-anchored: proteins attach to a lipid in the bilayer
-membrane trafficking and vesicle formation

Question 6

Passive Movement: across a cell membrane

Answer 6

Moves from a high to low concentration (no ATP required!!!!) - along the concentration gradient!!!

1) Simple diffusion: Allows the driect transport of molecules across the membrane
2) Facilitated Diffusion (Diffusion through a channel) : requires carrier or channel proteins to carry molecules across the membrane
-small, charged molecules

Question 7

Different types of Ion channels in passive movement

Answer 7

Ion channels: integral membrane proteins create aqueous pores

1) Voltage gated channels: activated by changes in the electric potential across the cell membrane
-only open when there is a charge

2) Ligand gated channels: activated by the binding of specific ligands to the channel receptor sites
- temporarily open when a ligand is binding