Cellular energetics concepts

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Why energy must be absorbed to start a chemical reaction

Energy is needed to weaken and break bonds in reactants so that new bonds can be created

How enzymes speed up the rate of chemical reactions

Lowering the activation energy

Suffix in most enzyme names

-ase

Part of the protein that makes enzymes highly specific

R group

Causes of denaturation

Extreme hot temperatures, pH changes, exposure to chemicals, salt concentration

Effect of cold temperatures on enzyme activity

Slowed reaction rate

Effect of warm temperatures on enzyme activity

Increases the speed of molecules and thus the collisions between enzymes and substrates, increasing the reaction rate

How pH causes denaturation

Changes in pH can disrupt hydrogen bonds that create the protein structure

Why denaturation can be reversible

The primary structure/amino acid sequence is not changed

Non-denaturing factors that affect enzyme activity

Presence of coenzymes/cofactors, amount of substrates, amount of enzymes

Why feedback inhibition can be good

Feedback inhibition is an important way to regulate cell metabolism and prevent the creation of too many products

Where energy is stored in endergonic reactions

In the covalent bonds of atoms in the products

Three parts of an ATP molecule

Adenine, ribose, three phosphate groups

Where the energy is stored in ATP

Between the second and third phosphates

Result of high entropy and low energy flow

Death

What a cell uses energy to do

Build and maintain its structure, manufacture products, move, grow, reproduce, maintain homeostasis

How the body brings in oxygen and removes carbon dioxide

Breathing

Glycolysis location

Cytosol

Glycolysis products

2 net ATP, 2 NADH, 2 pyruvate

What happens to pyruvate in the link reaction

It loses a carbon atom (which becomes part of a carbon dioxide molecule) and combines with coenzyme A to become acetyl-CoA

What happens in glycolysis

Glucose breaks down into pyruvate, and NAD+ accepts its electrons to become NADH

What happens in the Krebs cycle

Acetyl-CoA combines with a 4-carbon molecule to form a 6-carbon molecule, which loses two carbons and is then used again with another acetyl-CoA. The lost carbons become part of carbon dioxide

Krebs cycle products (1 spin)

2 carbon dioxide molecules, 1 ATP, 3 NADH, 1 FADH2

Goal of the Krebs cycle

Harvesting more high energy electrons to bring to the electron transport chain

Electron transport chain location

Inner membrane/cristae

What happens in the electron transport chain

Electrons are passed from electron acceptor to electron acceptor before merging with the terminal accepter, oxygen, to create water. As they are passed down, the energy is used to actively transport hydrogen ions against their concentration gradient to create a proton gradient

Products of oxidative phosphorylation

34 ATP

Result of decoupling of electron transport and oxidative phosphorylation

Generation of heat instead of ATP

Two types of fermentation

Lactic acid and alcohol

Two examples of lactic acid fermentation from the notes

Muscles during strenuous exercise and yogurt/cheese making

Alcohol fermentation products

Carbon dioxide and ethanol

Example of alcohol fermentation from the notes

Yeast

Examples of autotrophs

Plants, algae, some protists and prokaryotes

Where photosynthesis originated and its major effect

Prokaryotic autotrophs, which produced an oxygenated atmosphere

Visible light color with the most energy/shortest wavelengths

Violet

Visible light color with the least energy/longest wavelengths

Red

Chlorophyll A absorbed colors

Blue-violet and red

Chlorophyll A reflected color

Green

Chlorophyll B absorbed colors

Blue and orange

Chlorophyll B reflected colors

Yellow and green

What happens in Photosystems generally

Pigments absorb light energy and pass it from molecule to molecule until it reached the reaction center, which contains the primary electron acceptor

What happens in Photosystem II

The light energy excites an electron of chlorophyll P680, which is captured by the primary electron acceptor. Water is split,

Products of water split during Photosystem II and where they go

Electrons are given to chlorophyll P680, oxygen is released as oxygen gas, and hydrogen ions are left behind to increase their concentration inside the thylakoid

Where the energy to power the Calvin cycle comes from

Flow of hydrogen ions through ATP synthase

What happens in Photosystem I

The light energy excites an electron of chlorophyll P700, which is captured by the primary electron acceptor and replaced by the electron transport chain

Terminal electron acceptor in photosynthesis

NADP+

What happens in the carbon cycle

Carbon dioxide is converted into glucose using energy from ATP and electrons from NADPH

Specific name for what happens in the Calvin cycle

Carbon fixation

Why “dark cycle” is a misnomer for the Calvin cycle

It relies on products from the light-dependent reactions