VCU Bio 151 Exam 3 Merk

Photosynthesis

An anabolic and endergonic reaction.

Energy for photosynthesis

Sunlight (photons).

Water and CO₂ entry

Water through roots (osmosis), CO₂ through stomata.

Location of photosynthesis

Inside chloroplasts of green tissues.

Parts of photosynthesis

Light reactions and the Calvin cycle.

Location of light reactions

Thylakoid membrane.

Products of light reactions

ATP, NADPH, and O₂.

Location of the Calvin cycle

In the stroma.

Purpose of the Calvin cycle

To build glucose from CO₂ using ATP and NADPH.

Photosystem

A pigment-protein complex that captures light and transfers energy.

Chlorophyll A absorption

It releases an excited electron.

Electron replacement in PSII

By splitting water (photolysis), releasing O₂.

H⁺ pumping mechanism

The electron transport chain (ETC).

Enzyme synthesizing ATP in light reactions

ATP Synthase.

NADPH

An electron carrier used in the Calvin cycle.

Rubisco function

Fixes CO₂ to RuBP during the Calvin cycle.

First stable molecule in Calvin cycle

3-phosphoglycerate (3PG).

CO₂ needed for glucose

Six.

Photorespiration

Rubisco binds O₂ instead of CO₂, reducing sugar output.

Main fuel molecule for cells

Glucose.

Stages of cellular respiration

Glycolysis, Krebs cycle, ETC.

Location of glycolysis

Cytoplasm.

Products of glycolysis

2 pyruvate, 2 ATP (net), 2 NADH.

Pyruvate in aerobic conditions

It's converted into Acetyl CoA in mitochondria.

Krebs cycle products per glucose

6 NADH, 2 FADH₂, 2 GTP, 4 CO₂.

Location of the ETC

Inner mitochondrial membrane.

H⁺ gradient creation

Energy from electron transfers in the ETC.

Enzyme making ATP during respiration

ATP Synthase.

Final electron acceptor in the ETC

Oxygen.

Total ATP from one glucose in aerobic respiration

Around 32 ATP.

Products of fermentation

Lactic acid or ethanol + CO₂.

Purpose of fermentation

To regenerate NAD⁺ when O₂ is unavailable.

ATP production in fermentation

No, only glycolysis does (2 ATP per glucose).

Location of fermentation

In the cytoplasm.

Reasons for cell division

Growth, repair, and reproduction.

Steps for cell division

Signal, DNA replication, segregation, cytokinesis.

Division type in prokaryotes

Binary fission.

Mitosis purpose

Growth and repair in eukaryotic somatic cells.

Cell cycle

The repeating sequence of growth and division in a cell.

Parts of interphase

G₁, S, and G₂.

S phase

DNA is replicated.

Importance of checkpoints in cell cycle

They prevent damaged cells from dividing.

Proteins regulating the cycle

RB, cyclins, and CDKs.

Mitosis

The division of the nucleus and chromosomes.

Phases of mitosis

5 phases of mitosis.

5 phases of mitosis

Prophase, Prometaphase, Metaphase, Anaphase, Telophase.

Cytokinesis

Division of the cytoplasm.

Cytokinesis in plants vs animals

Plants: cell plate; Animals: cleavage furrow.

Apoptosis

Programmed cell death (clean, organized).

Triggers for apoptosis

DNA damage, development, immune regulation.

Main reasons for cell division

Growth, repair, reproduction.

Four key steps of cell division

Signal, DNA replication, DNA segregation, cytokinesis.

Binary fission

Prokaryotic cell division.

Mitosis

Eukaryotic somatic cell division.

Cell cycle

The series of events that cells go through to grow and divide.

Phases of interphase

G₁, S, G₂.

S phase

DNA replication.

Checkpoints in the cell cycle

To ensure DNA is undamaged and division is safe.

Proteins regulating the cycle

RB (stops the cycle), cyclins, CDKs (drive it forward).

Mitosis process

The nucleus and chromosomes divide.

Pyruvate in aerobic respiration

It's converted to Acetyl CoA in the mitochondria.

Krebs cycle production per glucose

6 NADH, 2 FADH₂, 2 GTP/ATP, 4 CO₂.

ETC location

In the inner mitochondrial membrane.

ATP production in the ETC

H⁺ gradient (proton motive force).

Enzyme making ATP in mitochondria

ATP Synthase.

ATP from one glucose in aerobic respiration

~32 ATP.

Fermentation products

Lactic acid or ethanol + CO₂.

Why fermentation occurs

To regenerate NAD⁺ when O₂ is not available.

ATP production in fermentation

No — only 2 ATP from glycolysis.

Fermentation location

Entirely in the cytoplasm.

Bacteria chromosomes

1 circular chromosome

Eukaryotic cell cycle

Series of phases to grow and divide

Non-dividing cells

G₀ phase (resting)

Subphases of interphase

G₁ - growth, S - DNA replication, G₂ - preparation for mitosis

S phase

DNA replication

Centromere

Region joining sister chromatids

Cell cycle checkpoints

Ensure proper progression

Checkpoints check for

DNA damage, replication completion, spindle attachment

RB protein function

Stops cycle until cell is ready

RB failure

Cell may become cancerous

Cyclins & CDKs

Regulate cycle progression

DNA damage effect on cycle

Activates p53 to block CDKs

Phases of mitosis

Prophase, Prometaphase, Metaphase, Anaphase, Telophase

Cytokinesis

Division of cytoplasm

DNA condensing

Chromatin becomes tightly coiled chromosomes

Purpose of mitosis

Make 2 identical daughter cells

S phase importance

So each daughter gets full DNA copy

Spindle

Microtubules that move chromosomes

Cytokinesis in plant vs animal cells

Plants form cell plate; animals pinch in

Ways cells die

Apoptosis and necrosis

Apoptosis vs necrosis

It's controlled and clean

Reasons for apoptosis

DNA damage, shaping development, immune system control

Most common fuel molecule

Glucose

Energy from glucose

Through glycolysis, Krebs cycle, and ETC

Aerobic respiration equation

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Glycolysis

Splitting of glucose into 2 pyruvate

Location of glycolysis

In the cytoplasm

Redox reaction

Transfer of electrons; reduction = gain e⁻, oxidation = lose e⁻

Reduced molecules energy

More energy

Pyruvate with O₂

It enters mitochondria for further breakdown