Comprehensive Biology: Organic Molecules, Cell Structures, and Metabolic Processes

Carbohydrates

End in -ose; primary energy source.

Dehydration

Getting rid of H2O to make polymers.

Hydrolysis

Add water to break sugar into monomers.

Lipids

Store energy, insulation, make up cell membrane.

Saturated Lipids

Maximum number of hydrogen bonds.

Unsaturated Lipids

Not maximum number of hydrogen bonds (double bonds).

Hydrophobic

Repels water (non-polar).

Hydrophilic

Attracts water (polar).

Phospholipid Molecular Structure

Make up cell membrane; phosphate group is hydrophilic, fatty acids are hydrophobic.

Bi-layer

Two layers of phospholipids; water on inside and outside of cell.

Peptide Bond

Links between one amino acid and another, forming polypeptide chains.

Structural Proteins

Building materials (non-working), ends in -in.

Enzymes

Working molecules, breaking things down, builds stuff up, catalyst.

Vmax

The maximum rate of an enzyme-catalyzed reaction.

Inhibition

When a molecule binds to an enzyme, reducing or stopping its activity.

Optimal Conditions

Specific temperature and pH levels where an enzyme works most efficiently.

DNA Structure

Double helix polymer; antiparallel arrangement.

Nucleotide Components

Adenine, Thymine, Guanine, Cytosine, Uracil.

Base-pairing

A corresponds with T(U) & G corresponds with C.

Gene

A recipe for a single protein.

Transcription

Process of converting DNA to messenger RNA (mRNA) in the nucleus.

Translation

Process of converting mRNA to protein at the ribosomes in the cytoplasm.

PolyA Tail

A long chain of adenine nucleotides added to the 3' end of mRNA.

Codons

Sequence of 3 RNA bases that correspond to a particular amino acid.

Promoter

Non-coding region on DNA that indicates the start of transcription.

Terminator

Region on DNA that indicates the end of transcription.

TATA Box

Sequence of nucleotides on DNA crucial to starting transcription.

Allosteric Control

Protein's function is regulated by a molecule binding to a site other than the active site.

Methylation

Enzyme attaches a methyl group to the gene which blocks transcription.

Acetylation

Enzyme attaches an acetyl group onto histone tail to create a conformation change which loosens the DNA strand and allows RNA polymerase to do its job.

miRNA (microRNA)

Short sequences of RNA that physically bind to mRNA on its complementary nucleotides to block tRNA from binding (stops translation).

Metabolism

Catabolism + Anabolism.

Catabolism

Breaking down of molecules.

Anabolism

Building up of molecules.

Spontaneous Reaction

Doesn't need energy for a reaction to occur.

Non-spontaneous Reaction

Needs energy for a reaction to occur.

Exergonic Reaction

Change in free energy is negative (no catalysts are needed for reactions to occur).

Endergonic Reaction

Change in free energy is positive (catalysts are needed for reactions to occur).

Activation Energy

Even in spontaneous reactions, activation energy is needed to break down the bonds.

G (Gibbs Free Energy)

Total amount of energy in a system.

Role of Enzymes

Catalysts that dramatically speed up chemical reactions in living things by lowering the activation energy.

Prokaryotic Cells

Cells that have no nucleus, with DNA out in the open.

Eukaryotic Cells

Cells that contain DNA in a nucleus.

Nucleus

Has a nuclear envelope, 4 phospholipid layers, functions to house DNA supply.

Ribosome

Site for protein synthesis.

Mitochondrion

Creates the cell supply of ATP, has 2 membranes, DNA floating around in mitochondria, makes proteins with ribosomes and DNA in its membrane.

Rough ER

Has ribosomes in the membrane, only makes proteins.

Smooth ER

Makes any chemical compound except proteins.

Golgi Apparatus

Packages molecules into vesicles for transport.

Lysosomes

Vestibular organelle that contains 'nasty' enzymes.

Vacuoles

Storage bubble.

Cytoplasm/Cytosol

The fluid component within the cell.

Chloroplast

Has own ribosomes and DNA, 2 membranes, makes glucose for autotrophs.

Phospholipid Bilayer

The fundamental structure of all cell membranes, forming a double layer of phospholipid molecules that separates the cell's interior from its exterior.

Microtubules

Hollow, cylindrical structures in the cytoplasm of eukaryotic cells that are part of the cytoskeleton.

Locomotion

Microtubules drive cell locomotion by forming structures like cilia and flagella, creating cell shape, and coordinating internal movement, often working with actin filaments.

Endosymbiont Hypothesis

An early eukaryotic cell engulfed the mitochondria but instead of breaking it down, it kept it to make ATP.

Semi-permeability

How much is allowed to pass through; cells only allow certain particles.

Active transport

Moving stuff against the law of diffusion.

Diffusion and gradients in transport

Gradients act as the 'push' for diffusion, allowing molecules to spread out until equilibrium.

Chemical cell signaling mechanisms: Reception

Involves protein transmembrane; receptors are specific to a particle ligand.

Conformation change

When ligand binds, it causes a conformation change in receptor protein which activates non-protein secondary messenger molecules.

Transduction

Passage of the message through cytoplasm.

Signal amplification

Involves activation of kinase through phosphorylation.

Response in cell signaling

Occurs in genes in DNA; activated kinases enter nucleus (transcription).

Osmosis

The diffusion of water across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

Photosynthesis

Autotrophs are organisms that make their own glucose.

Equation for photosynthesis

CO2 + H2O —> C6H12O6 + O2.

Role of light in photosynthesis

Provides the essential energy for photosynthesis, initiating the light-dependent reactions by being absorbed by pigments like chlorophyll.

Light stage of photosynthesis

Occurs in the thylakoid; electron gets excited by sun energy and travels down the Photosystem proteins.

Dark Cycle

Calvin Cycle where CO2 comes in and RuBisCo carboxylates RuBP.

RuBisCO

Located in chlorophyll, catalyzes carbon dioxide in organic compound with RuBP.

Transpiration

Extra H2O leaves the plant as water vapor.

Respiration equation

C6H12O6 + O2 —> CO2 + H2O.

Glycolysis

Creates 2 ATP by breaking glucose in half into pyruvates.

Krebs Cycle

Pyruvates made from Glycolysis enter the mitochondria and are broken apart into CO2, E-, and 2 ATPs.

Electron transport chain

NADH and FADH2 drop electrons off at the electron transport chain, creating 32 ATP.

Role of oxygen in respiration

The final electron acceptor in the electron transport chain.

Lactic acid fermentation

Starts after glycolysis; NADH dumps E- and H+ into pyruvate and becomes lactic acid, yielding 2 ATPs.

Alcoholic fermentation

Pyruvate is first decarboxylated (CO2 removed) and then NADH dumps E- onto the resultant molecule, creating alcohol and making 2 ATPs.