1st Law of Thermodynamics

Energy cannot be created or destroyed, it can only change forms.

The total amount of energy in the universe is constant.

2nd Law of Thermodynamics

In energy transfer, some energy is lost in a form that is unusable (usually heat).

This unusable energy is characterized by an increase of randomness and disorder in a system, A measure of this disorder is called ENTROPY

FREE ENERGY, or G

s the energy available to do work in a system. You calculate free energy by taking the product of the temperature T and entropy S and subtracting it from the ENTHALPY H.

Enthalpy

is the total energy in a molecule’s bonds

EXERGONIC

if the products of the reaction contains more free energy than the reactants. In this case, ΔG is negative, and energy is released. This is a spontaneous reaction.

ENDERGONIC

if the products of the reaction contains less free energy than the reactants. In this case, ΔG is positive, and energy is stored. This is NOT a spontaneous reaction.

ACTIVATION ENERGY

The energy needed for a reaction to occur is called

CATALYSIS

The process of influencing chemical bonds in a way that lowers activation energy is called

Carried out by CATALYSTS

ATP

Adenosine triphosphate is the energy currency of the cell.

The bonds between phosphate groups are high energy, but very unstable, making them easy to break and use as fuel.

SUBSTRATES

reactants in an enzyme-catalyzed reaction

Enzymes

are proteins that carry out catalysis

Competitive inhibitors

interfere with active site of an enzyme so substrates can’t bind to it

Allosteric inhibitors

bind to an allosteric site, which changes or stabilizes the shape of enzyme to inhibit it or activate it

METABOLISM

is the sum of all chemical reactions in an organism.

Many of these reactions occur in sequences called biochemical pathways, where the product of one reaction becomes the substrate for the next

Catabolic

pathways or reactions result in the breakdown of complex molecules into more simple ones while releasing energy

Anabolic

pathways or reactions result in the synthesis of complex molecules from simpler ones while storing energy

Glycolysis - Where? Yield?

• Anaerobic breakdown of glucose Catabolic pathway that occurs in both aerobic respiration and anaerobic respiration Takes place in the cytoplasm
• 2 ATP 2NADH 2PYRUVATE

Krebs /Citric Acid - Summary / Where / Yeild

• An amphibolic pathway that doesn’t produce much ATP, but provides electrons to power oxidative phosphorylation Takes place in the mitochondrial matrix (in eukaryotes)
• Net Yeild of two turns (Two Aceytl-CoA) is 2 ATP 6 NADH 2 FADH2 and 4CO2

oxidative phosphorylation - Summary/ Where/ Yeild

• Two parts: electron transport chain (ETC) and chemiosmosis Occurs in inner mitochondrial membrane Electrons are passed from one member of the transport chain to another in redox reactions; energy released is captured as a proton gradient, which is then used to make ATP in chemiosmosis
  
  net yield: 28 ATP

Fermentation

process of regenerating NAD+ with either an inorganic or organic compound serving as the final electron acceptor - occurs in the absence of oxygen

Lactic Acid Fermentation

➜ starts with glycolysis

➜ pyruvate is reduced by NADH to produce NAD+ and lactic acid

Ethanol Fermentation

starts with glycolysis

➜ pyruvate is decarboxylated

➜ intermediate acetaldehyde is reduced by NADH, producing NAD+ and ethanol

Photosynthesis

the process by which plants use solar energy to energize electrons, whose energy is then stored in the bonds of carbohydrates to be used as fuel

Stages of Photosynthesis

1-2 are light dependent and take place in the thylakoids

1 Capturing Energy from Sunlight
2 Using that energy to make ATP and reduce NADP to NADPH

3 is light independent and takes place in the stroma

3 Using ATP and NADPH to make organic molecules from CO2

PHOTON

• particle of light, and acts as though it is a discrete bundle of energy.

Light

has both wave and particle properties

is a form of electromagnetic radiation with a spectrum differentiated by its wavelength

Photoelectric Effect

is the removal of (excited) electrons from a molecule when light hits it.

How do Chloroplasts interact with Light

act as photoelectric devices, they absorb sunlight, and then transfer those excited electrons to a carrier

PIGMENTS

are substances that absorb visible light

molecule that is capable of absorbing certain wavelengths of light and reflecting others

ABSORPTION SPECTRUM

range of wavelengths of electromagnetic radiation absorbed by a given substance

ACTION SPECTRUM

of photosynthesis corresponds to the absorption spectrum of chlorophyll.

Chlorophyll b

an accessory pigment that absorbs blue and red-orange light and consequently has a yellowish-green tint - it aids chlorophyll A by absorbing additional colors

Chlorophyll a

form of chlorophyll that absorbs violet-blue and red light and consequently has a bluish-green color, the only pigment molecule that performs the photochemistry by getting excited and losing an electron to the electron transport chain.

Chloroplast Define / Structure

the organelle where photosynthesis takes place

it has 3 membranes - inner, outer, and thylakoid

Thylakoid

containds chlorophyll and is the site of photosynthesis and chemiosmis - arranged in stacks called grana

Stroma

Fluid surrounding thylakoids and is where the calvin cycle happens

Photo System II

The reaction center of PSII absorbs photons to excite electrons. PSII is oxidized and excited electrons are then transferred to the primary electron acceptor, then along the ETC to PSI. The missing electrons are replenished by splitting water and taking electrons from water molecules. This creates O2 in the process.

Photosystem I

By the time electrons make it to PSI, they have lost energy and need to be re-energized. PSI absorbs another photon to do so. The energy is transferred to the reaction center (P700) and then used to reduce an NADP+ into NADPH. The NADPH is then used in the Calvin Cycle.

Calvin cycle Define/Summary/Yield

• The Calvin cycle consists of the light-independent reactions of photosynthesis, synthesizing carbohydrates from atmospheric CO2 by using the ATP and NADPH produced by earlier reactions. It has three basic stages: carbon fixation, reduction, and regeneration of RuBP. Six turns of the cycle produce 1 molecule of glucose. Meaning we need 6 CO 2 to make 1 C 6 H 12 O 6 .

Step 1 of Calvin - Fixation

The enzyme RuBisCo catalyzes a reaction between 6 CO and 6 RuBP. The intermediate molecules are unstable and break into 2 halves. This creates 12 PGA (3-phosphoglyceric acid)

Step 2 of Calvin - Reduction

12 ATP and 12 NADPH are used to reduce the 12 PGA into 12 G3P (glyceraldehyde-3-phosphate).

Step 3 of Calvin - Regeneration

10 G3P are used to regenerate RuBP (ribulose bisphosphate), while 2 G3P are released into the cytoplasm to produce a sugar molecule. This stage uses 6 ATP.

chromatin

the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.

Chromosomes

are thread-like structures made of chromatin

They are responsible for carrying genetic information in the form of genes. This needs to be condensed in order to fit into the nucleus.

Homologous chromosomes

are maternal and paternal copies of the same chromosome

Sister chromatids

two replicas of a single chromosome, held together by cohesin proteins at their centromeres (after replication)

Kinetochores

attach to microtubules during mitosis

Phases of Cell Division

G1, S, G2, Mitosis, Cytokinesis (mitosis is 5 phases, covered separately)

Interphase

the part of the cell cycle between divisions, contains g1, S, and g2.

G1 phase

primary growth phase, cell grows, synthesizes MRNA, increases its supply of proteins and copies essential organelles, and prepares for DNA replication

S phase

cells replicate their centrioles (that form the mitotic spindle) and their DNA which is semi-condensed at this phase

G2

another growth phase, chromosomes condense further, cell grows and produces more proteins and organelles and prepares for mitosis

What are the 5 phases of mitosis

prophase, prometaphase, metaphase, anaphase, telophase

Prophase

Chromosomes condense enough to become visible

Spindle is assembled

Nuclear envelope breaks down

Prometaphase

Prometaphase

Microtubules from opposite poles of the cell attach to sister chromatids at the kinetochores

Chromosomes move to equator of cell

Metaphase

Chromosomes are lined up at the equator of the cell

Microtubules are under tension and cell is ready to divide.

Anaphase

Cohesin proteins are degraded

Microtubules pull sister chromatids apart by their kinetochores

Poles move apart and spindle fibers slide past each other

Telophase

Spindle apparatus disassembles

Nuclear envelope develops around chromosomes

Chromosomes uncoil for gene expression

Cytokinesis

The division of the cell body and cytoplasm

➔ In animal cells, a constricting belt of actin filaments pinches off daughter cells. This creates a cleavage furrow.

➔ In plant cells, a cell plate forms at the equator of the cell and grows outward until it divides the cell in half

Entropy

measure of randomness or disorder within a system

autotroph

make their own food

heterotroph

consume food made by autotrophs / must consume food/eat

chemiosmosis

process in which there is a production of ATP in cellular metabolism by the involvement of a proton gradient across a membrane

Electromagnetic energy

radiant energy that travels in waves at the speed of light. It can also be described as radiant energy, electromagnetic radiation, electromagnetic waves, light, or the movement of radiation. Electromagnetic radiation can transfer of heat.

wavelength

distance between consecutive points of equal position of a wave in a graphic representation - inversely proportional to the energy (smaller wave, higher energy, bigger waves lower energy)

ligand

chemical messenger released by one cell to signal either itself or a different cell - can be to grow/divide/stop

haploid

containing only one set of chromosomes

diploid

containing two sets of chromosomes