AP Bio Unit 3

Primary protein stucture

Amino acid sequence order

Secondary protein structure

Folding because of hydrogen bonds - α helix + β pleated sheet

Tertiary protein structure

Folding because of interactions between amino acids

Quaternary protein structure

Arrangement of MULTIPLE proteins together

Amino Acid structure

Amino group, R-group (determines function), carboxyl group

Peptide bond

Covalent bond linking amino acids, formed by dehydration synthesis

Denaturation

When proteins lose their shape (and probably function) due to disruptions

Enzymes

Protein that lowers activation energy in chemical reactions. Ends in -ase

Substrate

The molecule upon which the substrate acts

Active site

The region of an enzyme where a substrate binds

Anabolic

Enzyme reaction where molecules are being built and joined

Catabolic

Enzyme reaction where molecules are being broken down

Confirmation change/Induced fit

“Squeeze” where enzyme adapts to shape of substrate

Metabolism

All chemical reactions in the body

Environmental conditions on enzymes

Possible denaturation:

1. Temp - high temp affect hydrogen bonds, etc

2. pH change

3. Ionic concentration change (disrupts bonds)

Cofactors and coenzymes

Non-proteins that speed up enzyme reaction (ex. Vitamin B)

Competitive enzyme inhibitors

Resembles substrate and takes up their spot

Allosteric (uncompetitive) enzyme inhibitors

Doesn’t enter active site, binds to enzyme and changes enzyme shape

1st law of thermodynamics

Energy cannot be created or destroyed

2nd law of thermodynamics

Every time energy is used, the entropy increases ( hot → cold)

Energy input and output

Living things must obtain MORE energy than they use to keep living

Metabolic Pathway

The product of a reaction gets reused as a reactant of another pathway

Energy coupling

Pairing reactions that release energy w/ reactions that absorb energy to minimize energy lost

Energy and bonds

Breaking bond - uses energy

Forming bond - releases energy

Light Reactions

Input: Water and light energy

Output: Oxygen, ATP, NADPH

Light energy energizes electrons from water, which power the rest of the reaction.

H+ ions from water go through ATP synthase and are attached to ADP to make ATP. Also attached to NADP+ to make NADPH in NADP reductase

Photosystems II and I

Enzymes art of light reactions, II goes before I

Contains chlorophyll and is where electrons get energized

Thylakoid membrane

In chlorophyll, where light reactions take place

Stroma

Fluid in chlorophyll where dark reactions/Calvin cycle takes place

Calvin cycle

Inputs: CO2

Outputs: Sugars (ADP, NADP+, and H+ left over goes back to light reactions)

1. Carbon Fixation

2. Reduction (Adds carbon)

3. Regeneration (Leftover carbon-phosphates/G3P are recycled back into cycle)

Rubisco

Enzyme that pairs carbon and RuBP together at the start of Calvin cycle, ESSENTIAL for photosynthesis

Spongy/Palisade mesophyll

Where photosynthesis happens in leaves (think: -phyll)

Stomata

Plant pores that allow things in/out. Can open and close

C3 Plants

Most plants, typical photosynthesis. Carbons fixed 1 time

C4 Plants

Plants in humid/hot conditions (ex corn), photosynthesis is ALSO in bundle sheath cells. Carbons fixed 2 times

CAM Plants

Plants in hot and dry conditions (ex cacti), stomata open to collect CO2 ONLY at NIGHT to minimize water loss, Calvin cycle in daytime. Carbon fixed 2 times

Photolysis

Water broken down using light absorption. Happens in photosystem II

Photorespiration

Too much oxygen in plant, rubisco pairs oxygen instead of carbon in Calvin cycle. Inhibits photosynthesis