Bio Midterm Exam I

Why is water polar?

Unequal sharing of electrons → oxygen is more electronegative.

What bonds hold water molecules together?

Hydrogen bonds.

What are the 4 key properties of water?

Cohesion, adhesion, high specific heat, solvent.

What makes a molecule organic?

Contains carbon bonded to hydrogen.

What does a skeletal structure show?

Carbon backbone; hydrogens omitted; functional groups shown.

What is condensation (dehydration synthesis)?

Joins molecules, releases water.

What is hydrolysis?

Breaks molecules using water.

What is catabolism?

Breaks molecules → releases energy.

What is anabolism?

Builds molecules → requires energy.

What are the 3 differences between DNA and RNA?

DNA: deoxyribose, double-stranded, thymine; RNA: ribose, single-stranded, uracil.

What is the basic nucleotide structure?

Phosphate + sugar + nitrogenous base.

What is the structure of DNA?

Double helix, antiparallel strands, complementary base pairing.

What is the C:H:O ratio in carbohydrates?

1:2:1.

What are triose, pentose, and hexose?

3C, 5C, 6C sugars.

What are examples of monosaccharides?

Glucose, fructose, galactose.

What are disaccharides?

Sucrose, lactose, maltose.

What are polysaccharides?

Starch, glycogen, cellulose.

What is starch made of?

Amylose + amylopectin.

What is the difference between amylose and amylopectin?

Amylose = unbranched; Amylopectin = branched.

What is the structure of cellulose?

β-glucose, straight chains, hydrogen bonding.

What is the structure of glycogen?

Highly branched, compact energy storage.

How does carbohydrate structure relate to function?

Branching = faster glucose release; straight chains = strength.

What are the types of lipids?

Triglycerides, phospholipids, steroids.

What does a steroid look like?

4 fused carbon rings.

What is the structure of a triglyceride?

Glycerol + 3 fatty acids.

What is the structure of a phospholipid?

Glycerol + 2 fatty acids + phosphate head.

What is the difference between saturated and unsaturated fatty acids?

Saturated = no double bonds; Unsaturated = ≥1 double bond.

What is the difference between cis and trans unsaturated fatty acids?

Cis = bent (natural); Trans = straight (artificial).

How do lipids compare to carbohydrates as energy sources?

Lipids store more energy per gram, slower release.

What is the general amino acid structure?

NH₂, COOH, H, R-group on central carbon.

What determines protein folding?

R-group interactions.

What is primary protein structure?

Amino acid sequence.

What is secondary protein structure?

α-helix, β-pleated sheet (H-bonds).

What is tertiary protein structure?

3D folding (R-group interactions).

What is quaternary protein structure?

Multiple polypeptide chains.

What is Rubisco's function?

Carbon fixation.

What is insulin's function?

Hormone.

What is immunoglobulin's function?

Antibodies.

What is rhodopsin's function?

Vision.

What is collagen's function?

Structure.

What is spider silk's function?

Strength + flexibility.

What is the fluid mosaic model?

Phospholipid bilayer with moving proteins.

What is the difference between integral and peripheral proteins?

Integral = embedded; Peripheral = surface.

What is the magnification formula?

Magnification = image ÷ actual size.

What is the difference between prokaryotes and eukaryotes?

Prokaryotes: No nucleus, no membrane-bound organelles; Eukaryotes: Nucleus + organelles.

What are the key organelles and their functions?

Nucleus → DNA; Mitochondria → respiration; Ribosomes → protein synthesis; ER → protein/lipid transport; Golgi → modifies & packages; Chloroplast → photosynthesis; Vacuole → storage; Cell wall → support.

What is the significance of a high SA:V ratio?

Faster diffusion.

What happens in a hypotonic solution?

Cell gains water → swells.

What happens in an isotonic solution?

No net movement.

What happens in a hypertonic solution?

Cell loses water → shrinks.

What is the role of tRNA in translation?

Brings amino acids via anticodons.

What is the universal step in cellular respiration?

Glycolysis.

What processes require mitochondria?

Krebs cycle + ETC.

What are the factors affecting the rate of photosynthesis?

Light, CO₂, temperature.

What pigments are involved in photosynthesis?

Chlorophyll absorbs blue & red light.