Bisc 101 Week 5

What is the purpose of cellular respiration?

-To acquire glucose, which provides chemical energy to produce ATP.

-cellular respiration is any set of reactions that uses electrons harvested from high-energy molecules to produce ATP through ETC.

What are the inputs into cellular respiration? What are the outputs?

Input: Glucose, oxygen, ADP + P

Outputs: ATP, CO2, H2O.

4 Processes of Cellular Respiration

1. Glycolysis

2. Pyruvate processing

3. Citric acid cycle

4. ETC and oxidative phosphorylation

Glycolysis

6 carbon sugar → 2 pyruvates

ADP+P → ATP

NAD+ → NADH

occurs in cytosol for both Eukaryotes and Prokaryotes

Pyruvate Processing

Pyruvate(2 carbons) → Acetyl CoA (2 carbons) and CO2

NAD+ → NADH

eukaryotes: mitochondrial matrix

prokaryotes: cytosol

Citric Acid Cycle

Acetyl CoA → CO2

ADP+P → ATP

NAD+ → NADH

FAD → FADH2

eukaryotes: mitochondrial matrix

prokaryotes: cytosol

ETC and oxidative phosphorylation

ETC:

-Oxidation of NADH and FADH2.

-Electrons from NADH and FADH2 move through ETC which releases energy used to transport protons across the inner mitochondrial membrane, creating a proton gradient.

-Oxygen is the final electron acceptor and it forms water as a by-product

O.P:

-The potential energy stored in the proton gradient is used to spin components of the ATP synthase to produce ATP by combining ADP+P.

-This process is responsible for most of the ATP made by cellular respiration.

prokaryotes: plasma membrane.

Eukaryotes: inner mitochondrial membrane.

ATP Synthase

-combines ADP and phosphate as it spins, creating ATP.

Why does electron transport and chemiosmosis need a membrane?

Without a membrane, no proton gradient can form. Which prevents protons from flowing through the ETC and ultimately producing ATP.

Fermentation

-To replenish supply of NAD+ for glycolysis

-Occurs in the cytosol when an electron transport chain is not present or it is inactive due to an insufficient amount of the final electron acceptor.

Produces lactate in humans

Inputs are Pyruvate & NADH

Similarities between C.R. and Fermentation

both processes used to make ATP and neither requires oxygen

Differences between C.R. and Fermentation

-Nearly every organism can perform some type of fermentation but only certain prokaryotes can do anaerobic respiration.

-cellular respiration uses an ETC and ATP synthase while fermentation does not.

-In cellular respiration glucose is converted into CO2, while in fermentation glucose is converted into an organic molecule such as lactate.

-cellular respiration also produces more ATPs per glucose.

Photosynthesis

-The use of sunlight to manufacture carbohydrates.

Overall reaction: CO2 + H2O + light energy -> (CH2O)n + O2

• light capturing reaction

• calvin cycle

The light-capturing reactions

-Produces oxygen from water.

-Light energy is transformed to chemical energy in the form of ATP and NADPH

The Calvin cycle

-Produces sugar from carbon dioxide.

-The ATP and NADPH produced in the light capturing reactions are used to reduce carbon dioxide to sugar. Also creates ADP+P.

-Occurs in the stroma.

NADPH

-electron carrier produced in light reactions; used to reduce CO₂ in the Calvin cycle.

Carbohydrates

-Glucose: Monosaccharide linked to glycosidic bond (repeat)

-Starch: polysaccharide of glucose. Can be branched or linear

General roles: cell & molecule identity, cell structure, AND ENERGY

Catabolism

releases energy. breaking big molecules down into subunits: RELEASING ENERGY

Anabolism

Building big molecules from subunits: USES ENERGY

Meiosis

production of sperm and eggs, which are the gametes. (In plants, spores)

daughter cells different from parent cell

Mitosis

production of somatic cells.

daughter cells identical to parent cell

Cytokinesis

division of the cytoplasm into two distinct cells.

How Do Cells Replicate?

1. copying the DNA.

2. separating the copies.

3. dividing the cytoplasm to create two complete cells.

What Is a Chromosome?

• Chromosomes consist of a single long DNA double helix that is wrapped around proteins, called histones.

• Before mitosis, each chromosome is replicated. As mitosis starts, the chromosomes condenses. Then one copy of each chromosome is distributed to each of two daughter cells.

The Cell cycle

Interphase:

1. G1 phase

2. S phase

3. G2 phase

M phase:

• PMAT

• Cytokinesis

G1 phase

part of interphase, growth: accumulating the building blocks of chromosomal DNA and energy

S phase

part of interphase, DNA replication occurs

G2 phase

part of interphase, growth, preparation for cell division

Cell cycle checkpoints

• control mechanisms

• G1 checkpoint, the G2/M checkpoint, and the M checkpoint.

Centromere

Chromosome Handle

Microtubules

pulls chromosomes apart during mitosis

centrosomes

microtubule-organising centre in eukaryotes during mitosis

Kinetochore

holds DNA and microtubule together at centromere

Prophase

• Chromosomes Condense

• Spindle Apparatus forms at centriole

Prometaphase

• nuclear envelope dissolves

• microtubules make contact with chromosomes

Metaphase

• Microtubules move chromosomes to center of cell

Anaphase

• Microtubules pull sister chromatids apart

Telophase

• sister chromatids arrive at opposite poles of cell

• nuclear envelope forms around each set

Cytokinesis

• Division of cell cytoplasm into two daughter cells

• Product = 2 diploid cells

MPF

• m-phase promoting factor in all eukaryotes