UIUC MCB 150 Exam 1

Cell Theory

all organisms are made of cells, all existing cells are produced by other living cells, the cell is the most basic unit of life

Prokaryotes

Cells that do not contain nuclei, bacteria and archaea

-singular circular chromosome

-no membrane bound organelles

-nucleolus

Archaea

Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan

-live in harsh environments

Eukaryotes

Cells that contain nuclei

-multiple linear chromosomes in the nucleus

-extensive cytoskeleton

Central Dogma

DNA-transcription-RNA-translation-protein

Bacteria

Domain of unicellular prokaryotes that have cell walls containing peptidoglycan

Covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Polar: uneven sharing

Nonpolar: even sharing

Ionic bonds

Formed when one or more electrons are transferred from one atom to another

Macromolecules

any large molecules made up of smaller molecules (monomers) joined together into a polymer

Condensation reactions

a chemical reaction in which two or more molecules combine to produce water or another simple molecule

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Nucleoid

A dense region of DNA in a prokaryotic cell.

Plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

Ribosomes

site of protein synthesis

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

-Prokaryotes have less extensive cytoskeleton

Cell wall

a fibrous layer found outside the plasma membrane of most bacteria and archaea and eukaryotes

flagellum

A long, hairlike structure that grows out of a cell and enables the cell to move.

fimbria

A short, hairlike appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells.

Archaea are more closely related to _____ than _____.

Eukaryotes, bacterial

Nucleus

-contains chromosomes

-double membraned

-contains sites where the RNA are processed into their functional form

nuclear envelope

Double membrane perforated with pores that control the flow of materials in and out of the nucleus.

Nucleoulus

the area in the nucleus of a cell where ribosomes are produced

Endoplasmic Reticulum

A system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids.

Rough Endoplasmic Reticulum

-Dotted with ribosomes

-Involved in synthesizing plasma membrane proteins, secreted proteins, and proteins located in the ER, Golgi Apparatus, and lysosomes

-Proteins move into the interior, "lumen", undergo folding and other types of processing

Smooth Endoplasmic Reticulum

-lacks ribosomes

-Involved in synthesizing lipids and removing toxic molecules

-Contains enzymes that catalyze reactions involving lipids

-functions as a reservoir for calcium ions

Golgi apparatus

-A system of membranes that modifies and packages proteins for export by the cell

-Cis: closest to nucleus, receives

Lysosomes

-cell organelle filled with enzymes needed to break down certain materials in the cell

-Imports H+ to lower pH

endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

Vacuoles

Used for bulk storage of water, pigments, oils, or other substances

Peroxisomes

small membrane enclosed organelles filled with enzymes

-oxidizes fatty acids and other compounds rendering them harmless

Mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

-form a series of cristae in the inner membrane

>site of electron transport chain and ATP synthase

Mitochondrial DNA

A small amount of DNA that is located in the mitochondria of cells. Mitochondrial DNA is inherited only through the mother.

Chloroplasts

organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis

-double membraned

-thylakoid: a membrane bound network of flattened saclike structures inside a plant chloroplast

extracellular matrix

The substance in which animal tissue cells are embedded, consisting of protein and polysaccharides.

Microfilaments

Long, thin fibers that function in the movement and support of the cell

Microtubules

intracellular highways for transporting vesicles and organelles

-also required for cellular locomotion via flagella and cilia

Intermediate filaments

anchor organelles and intercellular junctions

Carbohydrates

Macromolecules=Polysaccharides

-used for energy sources, cell walls, cell identification and recognition

Carbohydrates formula

Cn(H2O)n

-subtract 1 H2O for every glycosidic bond

Hexose

6 carbon sugar

Pentose

5 carbon sugar

Triose

3 carbon sugar

alpha Glucose

glucose where on C1 H on top, OH on bottom

beta glucose

glucose where on C1 OH on top, H on bottom

Aldose sugar

Carbonyl at the end of a monosaccharide

-same number of members in ring as carbons

-one carbon on outside of ring

Ketose sugar

carbonyl group within carbon skeleton

-one less members in ring as carbons

-two carbons on outside of ring

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

-results in polysaccharides

glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

-Helical, highly branched

-Unbranched: a-1,4-glyocidic links

-Branched: a-1,6-glycocidic links

Starch

A storage polysaccharide in plants consisting entirely of glucose.

-helical, mixture of branched and unbranched (less than glycogen)

-Unbranched: a-1,4-glyocidic links

-Branched: a-1,6-glycocidic links

Cellulose

polysaccharide consisting of glucose monomers that reinforces plant-cell walls

-linear, unbranched polymer of glucose

-Unbranched: B-1,4-glycosidic links

phosphorylase

An enzyme that breaks down glycogen by catalyzing hydrolysis of the a-glycosidic linkages between the glucose residues.

Glucose

A simple sugar that is an important source of energy.

-Aldose

-monosaccharide

-Hexose

Fructose

-ketose

-Hexose

Galactose

-aldose

-Hexose

Glucose + fructose

sucrose

glucose + galactose

lactose

glucose + glucose

maltose

Amino group

(—NH2) a functional group composed of nitrogen atom bonded to two hydrogen atoms and to the carbon skeleton. Can act as a base in solution, accepting a hydrogen ion and acquiring a charge of +1.

carboxyl group

-COOH

A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group.

carbonyl group

a chemical group consisting of a carbon atom linked by a double bond to an oxygen atom

-at the end of Aldehydes

-inside ketones chains

hydroxyl group

OH-

-highly polar, makes compounds more soluble

phosphate group

A functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms

sulfhydryl group

A functional group consisting of a sulfur atom bonded to a hydrogen atom (—SH).

Amino Acids

a simple organic compound containing both a carboxyl (—COOH) and an amino (—NH2) group.

-monomers of proteins

-Amino acids amino group connects to incoming carboxyl group

R group (side chain)

part of amino acid that determines the molecule's physical and chemical properties

Peptide bond

The chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

disulfide bonds (sulfhydryl)

Strong chemical side bonds formed when the sulfur atoms in two adjacent protein chains are joined together.

primary structure of protein

the amino acid sequence of the polypeptide chain

secondary structure of protein

local structure of alpha helix or beta pleated sheets; stabilized by peptide-linkage hydrogen bonds (no R-group interactions at this level)

tertiary structure

The third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain.

native conformation of a protein

the most stable three dimensional structure

quaternary structure of a protein

protein structure is a protein consisting of more than one folded amino acid chain

Dipeptide

Two amino acids bonded together

Oligopeptide

4-9 amino acids

Polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

Stabilizing forces in protein

-Hydrogen bonds

-Hydrophobic clusters

-Ionic bonds

-Van der Waals Interactions

-Disulfide linkages

Heterodimer

a protein composed of two polypeptide chains differing in composition in the order, number, or kind of their amino acid residues

homodimer

two of the same polypeptides

amylose

unbranched starch

amylopectin

branched starch

The surface area-to-volume ratio of a cell

Accounts for the size limit of cells

activation energy (Ea)

The amount of energy required to produce the transition state of a chemical reaction. If the activation energy for a reaction is very high, the reaction occurs very slowly. Enzymes (and other catalysts) increase reaction rates by reducing activation energy.

transition state

a high-energy intermediate state of the reactants during a chemical reaction that must be achieved for the reaction to proceed

Substrates

the reactants of enzyme-catalyzed reactions

Catalyst (enzyme)

a molecule that influences the rate of chemical reactions but is not consumed in the reaction

induced fit

Brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction.

Enzyme

a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.

-lower Ea

Cofactors

Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis

coenzyme

If the cofactor is an organic molecule.

prosthetic group

A non-protein, but organic, molecule (such as vitamin) that is covalently bound to an enzyme as part of the active site.

Chaperones

help proteins fold correctly

competetive inhibition

Inhibitor molecule attaches to the active site and the substrates are unable to bind temporarily

allosteric regulation

The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.

nucleic acids

polymers that are made up of monomers called nucleotides

nucleic acids are made of

5 carbon sugar, phosphate group, nitrogenous base

purines

Adenine and Guanine (double ring)

Pyrimidines

cytosine, thymine, uracil(single ring)

phosphodiester linkage

covalent bonds that join adjacent nucleotides between the -OH group of the 3' carbon of one nucleotide and the phosphate on the 5' carbon of the next

Lipid

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen

-do not dissolve in water.