BIOSCI 101 Short Answers Flashcards
What are the 3 Parameters of Magnification?
Magnification, Resolution, Contrast.
What is a Light Microscope used for?
To visualise cells and large subnuclear organelles.
What is an Electron Microscope used for?
Electron beam sees through specimen or onto its surface.
What are the 3 Differences between SEM and TEM?
SEM - 10nm res, onto surface, 3D images.
TEM - 2nm res, internal structure, through specimen
What do Plant Cells have that Animal Cells don’t?
Cellulose cell wall, central vacuole, chloroplasts.
What are the 2 Key Features of a Mitochondria?
Respiratory enzymes in inner membrane/matrix, contain own DNA/ribosomes.
What are the 2 Key Features of a Chloroplast?
Bound by outer and inner membrane, has thylakoids.
What are the 3 Functions of the Cytoskeleton?
Maintains cell shape, facilitates cell movement and movement of cell components.
What are the 3 Types of Cytoskeletal Filaments?
Microtubules, microfilaments, intermediate filaments.
Describe the Process that takes place in the ER.
Vesicle fuses with golgi to empty proteins, proteins are modified, budding off into vesicles.
What is the Function of Intermediate Filaments?
Anchors.
What is the Function of Microtubules?
Road network for organelles.
What is the order of Cell Fractionation?
Tissue cells, homogenisation, homogenate, centrifugation.
What is the Purpose of Cell Fractionation?
Isolates cell components based on size and density.
How is Centrifuge Speed related to Visible Components?
Slow speeds = Larger organelles.
How are Polymers Assembled and Degraded?
Assembly (dehydration) and degradation (hydrolysis).
Why are Lipids Insoluble?
Non-polar hydrocarbon chains.
What is the Difference between Saturated and Unsaturated Fats?
Saturated - solid at room temp.
Unsaturated - liquid at room temp.
What are the 3 Functions of Polysaccharides?
Energy/fuel, structural support, carbs can be added to improve other functions.
What are the Major Cell Characteristics?
Arise from preexisting cells, genetic info as DNA, proteins are synthesised on ribosomes, membrane encloses every cell.
What are Mitochondria?
Site of cellular respiration where oxygen and food are combined to make energy (ATP).
What is the Chemical Composition of Cells?
50%C, 10%N, 15%H, 20%O, 5% other.
What are the 3 Types of Polysaccharides?
Mono (1), Di (2), Poly (many).
How are Saccharides Stored in Plants?
Starch: granules in plastids, glucose released by hydrolysis.
How are Saccharides Stored in Animals?
Glycogen: in liver/muscle cells, glucose released by hydrolysis.
How can Lipids be Identified?
Long hydrocarbon chain, glycerol group, only contain H,C,O.
How can Proteins be Identified?
Contains C,H,O,N, contains NH2 group and an acid group.
How can Saccharides be Identified?
Only contains H,C,O, 1C:2H:1O ratio, arranged as a ring.
Describe the Phospholipid Bilayer.
7-8nm thick, made of hydrophilic head and hydrophobic tail.
How Fluid are Phospholipids?
Lateral movement happens 10 million times a second.
Which Experiment proved Cell Fusion was Viable?
Mouse cell + human cell, hybrid cell, mixed proteins in 1 hour.
What are the 6 Functions of Membrane Proteins?
Enzymatic activity, signal transduction, cell-cell recognition, attachment to cytoskeleton and ECM, intercellular joining, transport.
What are some Examples of Active and Passive Transport?
Passive - Diffusion, facilitated
Active - Na/K Pump
Describe the Main Components of Active Transport?
Molecules move across membrane against concentration gradient, requires energy.
What are the Functions of Transport Proteins?
Provide selectivity, can increase of transport, continuously recycled, rate of transport limited.
What are the 3 Types if Endocytosis?
Phagocytosis, pinocytosis, receptor mediated endocytosis.
What are Nucleotides Composed?
Phosphate group, sugar/pentose, nitrogenous base.
How is Fluidity Impacted?
By saturation - unsaturated = greater fluidity.
How is Fluidity Maintained?
By squeezing of cholesterol at v. cold temperatures.
What are Integral Proteins?
Inserted into cell membrane associating with hydrophobic region.
What are Peripheral Proteins?
Outside of membrane.
What are the Functions of a Protein Extension?
Cell communication with outside environment, anchoring.
How many Connexins form a Gap Junction?
6.
What is the Function of Plasmodesmata?
Allow RNA/small proteins to move between cells.
When is Facilitated Diffusion required?
Hydrophylic can’t pass hydrophobic layer.
What is Selectivity?
Only select proteins can pass through.
What is ‘Cell Eating’?
Pseudopodium sent out to engulf food particle.
What is ‘Cell Drinking’?
Gulps of outside molecules.
What does ‘Receptor Mediated’ mean?
Bind to specific molecules.
Which Amino Acids are Hydrophobic and Hydrophilic?
Non-polar: Hydrophobic
Polar: Hydrophilic
Electrically: Hydrophilic
What is the Function of Peptide Bonds?
Link carboxyl group of one amino acid to amino group of the next.
What is RNA Responsible for?
Information in RNA determines amino acid sequence.
Where is the Alpha Helix Found?
In the regions of transmembrane proteins that cross the bilayer.
Where are Beta Pleated Sheets Found?
In the core of many globular proteins.
What are the 2 Functions of Chaperonins?
Assists the folding of proteins, check correct folding has occurred.
How does Heat Denature Structures?
Breaks weak bonds.
How does pH Denature Structures?
Changes ionisation patterns of R groups.
How do Reducing Agents Denature Structures?
Reduce S=S bonds to SH.
How do Organic Solvents Denature Structures?
Disturb hydrophobic and hydrophilic interactions.
How do Detergents Denature Structures?
Disrupt hydrophobic interactions.
What is an Anabolic Reaction?
Energy enters reaction and is stored in molecular products. Large molecules synthesised from small molecules.
What is a Catabolic Reaction?
Energy exits reaction and is available for cellular work. Breakdown of large molecules into energy + small molecules.
What is Transport Work?
ATP phosphorylates transport proteins.
What is Mechanical Work?
ATP binds non-covalently to motor proteins and then is hydrolysed.