Metabolism

What’s the main difference between catabolism and anabolism?

A. Catabolism builds, anabolism breaks

B. Catabolism breaks down, anabolism builds up

C. Both build molecules

D. Neither uses energy

Catabolism breaks down, anabolism builds up

What’s the main function of an enzyme?

A. It adds energy to a reaction

B. It slows reactions down

C. It acts as a catalyst, speeding reactions without being used up

D. It changes the chemical products

It acts as a catalyst, speeding reactions without being used up

Which is a constitutive enzyme?

A. One made only when needed

B. One that’s always present in the cell

C. One that is denatured easily

D. One that requires an inhibitor

One that’s always present in the cell

A molecule blocking an enzyme’s active site is an example of:

A. Non-competitive inhibition

B. Feedback inhibition

C. Competitive inhibition

D. Activation energy reduction

Competitive inhibition

Which situation best describes non-competitive inhibition?

A. A molecule competes for the active site

B. A molecule binds somewhere else, changing the enzyme’s shape

C. A molecule permanently destroys the enzyme

D. They enzyme breaks down spontaneously

A molecule binds somewhere else, changing the enzyme’s shape

What two factors mainly affect enzyme activity?

A. Temperature and water availability

B. Temperature and pH

C. Light and salinity

D. Pressure and time

Temperature and pH

What does oxidation mean?

A. Gain of electrons

B. Loss of electrons

C. Gain of protons

D. Formation of water

loss of electrons

What’s happening when NAD+ becomes NADH

A. It loses an electron

B. It gains an electron and a proton (H)

C. It breaks down into ATP

D. It is oxidized

It gains an electron and a proton (H)

Which of these does not require oxygen?

A. Aerobic respiration

B. Electron transport chain

C. Glycolysis

D. Krebs cycle

Glycolysis

What are the end products of glycolysis?

A. Glucose and ATP

B. Pyruvate, ATP, NADH

C. CO2 and H2O

D. Lactic acid and ATP

Pyruvate, ATP, NADH

During fermentation, the cell’s main goal is to:

A. Produce more ATP directly

B. Regenerate NAD+ for glycolysis to continue

C. Break down proteins

D. Form new glucose molecules

Regenerate NAD+ for glycolysis to continue

In the presence of oxygen, pyruvate goes into:

A. Fermentation

B. Aerobic respiration

C. Photosynthesis

D. Denaturation

Aerobic respiration

Aerobic respiration makes approximately how much ATP per glucose?

A. 2

B. 4

C. 18

D. 36-38

36-38

Where does glycolysis occur in both prokaryotes and eukaryotes?

A. Mitochondria

B. Cell membrane

C. Cytoplasm

D. Nucleus

Cytoplasm

Where does the electron transport chain happen in prokaryotes?

A. Cell membrane

B. Cytoplasm

C. Ribosome

D. Nucleus

Cell membrane

Which term refers to the total of all chemical reactions in an organism?

A. Metabolism

B. Respiration

C. Photosynthesis

D. Catalysis

Metabolism

What happens to enzyme when they get too hot?

A. They work faster

B. They denature

C. They freeze

D. They oxidize

They denature

What kind of enzyme is produced only when needed?

A. Constitutive

B. Regulated

C. Competitive

D. Denatured

Regulated

Which is a reduction reaction?

A. NADH → NAD+

B. NAD+ → NADH

C. Pyruvate → glucose

D. ATP → ADP

NAD+ → NADH

Which process produces CO2, H2O, and shit ton of ATP?

A. Fermentation

B. Aerobic respiration

C. Glycolysis

D. Photosynthesis

Aerobic respiration

The removal of electrons is called _____

Oxidation

The addition of electrons is called _____

Reduction

The sum of all chemical reactions in a cell = _____

Metabolism

Enzymes lower the _____ needed to start a reaction.

Activation energy

Glycolysis makes ___ ATP per glucose molecule.

2

Fermentation produces products like ____ and _____.

Ethanol and lactic acid, sometimes CO2

Aerobic respiration happens in the ____ of eukaryotes.

Mitochondria

Prokaryotes perform aerobic respiration on their _____.

Cell membrane

The molecule NADH acts as an _____ carrier.

Electron

An enzyme that’s always available= _____ enzyme.

Constitutive

Explain how enzymes are like workers on an assembly line

Each enzyme, worker, has one specific task, they’re reusable and efficient

What’s the relationship between catabolism and anabolism?

Catabolism breaks things down to provide energy; anabolism uses that energy to build

Why do cells needs both glycolysis and fermentation when oxygen isn’t around?

Fermentation regenerates NAD+ so glycolysis can keep running and make small amounts of ATP

Describe how redox reactions help generate ATP.

Electrons from NADH/FADH2 power ATP production through the electron transport chain

Explain why prokaryotes and eukaryotes perform the same reactions differently.

Eukaryotes use mitochondria for compartmentalization; prokaryotes use their membrane since they lack organelles

Metabolism

The sum of all chemical reactions in an organism, catabolism + anabolism

Catabolism

breaking down molecules, which releases energy

Anabolism

Building molecules, which requires energy

Enzyme

Protein catalyst that speeds up reactions without being used up

Constitutive enzymes

Always present and active in the cell

Regulated enzyme

Made only when needed; controlled production

Competitive inhibition

Fake substrate blocks the enzyme’s active site

Non-competitive inhibition

Molecule binds somewhere else, changing the active site shape

Denaturation

Enzyme loses shape and function due to wrong pH or temperature

Oxidation

Loss of electrol

OILRIG

Oxidation is loss, reduction is gain

Reduction

Gain of electrons

NAD+ → NADH

Nad+ gains electrons and Hydrogen, acts as a charged energy carrier

Glycolysis process and where it occurs

Glucose leads to 2 pyruvate, 2 ATP, 2 NADH (occurs in cytoplasm)

Fermentation process-ish

Anaerobic process; pyruvate → lactic acid or ethanol + CO2; regenerates NAD

Aerobic respiration reaction in mitochondria

Pyruvate + O2 produces CO2 + H2O + 36 ATP

Electron transport chain (ETC)

Uses electrons from NADH/FADH2 to make tons of ATP

Location of glycolysis

Cytoplasm, both prokaryotes and eukaryotes

Location of aerobic respiration (eukaryote)

Mitochondria

Location of aerobic respiration (prokaryotes)

Cell membrane

Main purpose of fermentation

Regenerate NAD so glycolysis can keep making ATP without oxygen

ATP yield comparison in glycolysis, fermentation, and aerobic

2, 2, 36

Where does glycolysis occur in eukaryotes

cytoplasm

where does glycolysis occur in prokaryotes

cytoplasm

Glycolysis starts with _ glucose ( _ carbons)

1 glucose, 6 carbons

glycolysis ends with _ pyruvic acids ( _ carbons each)

2 pyruvic acids, 3 carbons

net products of glycolysis

2 atp and 2 nadh

what is the purpose of the intermediate step

to trim the pyruvate since the kreb cycle needs 2 carbons, not three

where does the intermediate step occur in eukaryotes

mitochondria

where does the intermediate step occur in prokaryotes

cytoplasm

what happens in the intermediate step

each pyruvate loses one carbon, which leaves as co2. when you lose a carbon you release electrons, oxidation. those electrons go from nad+ to nadh. the 2 carbons that are left attach to coenzyme a = acetyl-coa

How many times does the intermediate step happen

twice

What do you have after the intermediate step

2 Acetyl-CoA, 2 CO2, 2 NADH

where does the krebs cycle occur in eukaryotes

mitochondrial matrix

where does the krebs cycle occur in prokaryotes

cytoplasm

what is the purpose of the krebs cycle

to rip apart acetyl-coa and capture the energy as nadh, fadh2, and a tiny bit of atp

First step of krebs cycle

2 carbon acetyl coa joins a 4 carbon molecule to make citric acid, a 6 carbon structure

second step of krebs cycle

one carbon gets chopped off, co2 is released and electrons go to nadh

first and second step of krebs cycle

2 carbon acetyl coa joins a 4 carbon molecule to make citric acid, a 6 carbon structure. one carbon gets chopped off, co2 is released and electrons go to nadh

third step of krebs cycle

another carbon gets chopped off, resulting in more co2 and more nadh

second and third steps of krebs cycle

one carbon gets chopped off, co2 is released and electrons go to nadh. another carbon gets chopped off, resulting in more co2 and more nadh

fourth step of krebs cycle

back to the original 4 carbon molecule and it is ready to start again, along the way the cycle makes atp, fadh2, and even more nadh

All steps of krebs cycle

2 carbon acetyl coa joins a 4 carbons molecule to make citric acid, a 6 carbon structure. one carbon gets chopped off, co2 is released and electrons go to nadh. another carbon gets chopped off, resulting in more co2 and more nadh. back to the original 4 carbon molecule and it is ready to start again, along the way the cycle makes atp, fadh2, and even more nadh

How many CO2 per glucose (2 Acetyl-CoA) in krebs cycle?

4

How many NADH per glucose (2 Acetyl-CoA) in krebs cycle?

6

How many FADH₂ per glucose (2 Acetyl-CoA) in krebs cycle?

2

How many ATP per glucose (2 Acetyl-CoA) in krebs cycle?

2

What is the most important product of the krebs cycle and why

NADH and FADH2, they carry the electrons that will power the next stage, etc

T/F

The Krebs Cycle makes a lot of ATP

false, it doesnt make a lot but sets you up for the jackpot

where does the electron transport chain (ETC) occur in eukaryotes?

inner membrane of mitochondria

where does the electron transport chain (ETC) occur in prokaryotes

plasma membrane

What is the first thing that happens in the ETC

NADH and FADH2 dump their electrons onto the ETC

what is the ETC

a chain of proteins in a membrane

What happens as electrons move down the etc

they release energy

What is the released energy used for in ETC

the energy is used to pump protons/H across the membrane, which builds a proton gradient

What does the gradient do regarding etc

supplies potential energy

what is the most important thing from ETC

the proton gradient

Once the proton dam builds up, the only way for protons to flow back across the membrane is through

an enzyme called ATP synthase

what happens as protons flow through ATP synthase

it spins like a molecular turbine, this movement generates ATP

ETC builds the gradient→

chemiosmosis (atp synthase) uses it to make atp

how much atp after glycolysis

2

how much atp after intermediate step

0

how much atp after krebs cycle

2 atp

how much atp after etc and chemiosmosis

around 34

total atp after aerobic respiration

around 38