BIO130 MIDTERM

What is a cell

baic unit of life 

Cytoplasm 

the contents inside of the cell (organells)

Cytosal

jelly-like liquid inside the cell, surroinding the organells 

Prokaryote 

organism with no nucleus 

Eukaryote 

organism with a nucelus 

Nucleic Acid

a polymer of nucelotides that encodes and transmits genetic info

Protein 

the key structural and functional molecule that does the work of the cell

Transcription 

The synthesis of RNA from a DNA template 

Translation 

the synthesis of a polypeptide chain corresponding to the coding sequence in a molecule messenger RNA

Vacuole 

membrane-bound organelle that contains fluid, ions, and other molecules 

Lysosome

organelle with digestive enzymes that breaks down waste and forgien invaders 

Cytoskeleton

network of protien fibers that gives the cell structure and helps with movement

Peroxisome

organelle that breaks down fatty acids and neutralizes toxic sustances 

Plasma Membrane 

phospholipid bilayer that surrounds the cell and controls what enters/exits the cell

Cell Wall

rigid layer outside the plant cell that provides structural support and protection 

Organelle

specialized structure within a cell that performs a specific job to keep the cell functioning 

Nucelus

membrane-bound organelle that stores DNA and controls cellular activites 

Nuclear Envelope 

double-membrane surrounding the nucelus that regulates the movement of materials in/out 

Nucleolus

a dense region inside the nucelus responisble for producing and assembling ribosomes 

Mitochondrion 

A organelle that generates the cell's chemical energy 

Chloroplast 

An organelle in plant cells that conducts photosynthesis 

Endoplasmic Reticulum (smooth & rough)

network of membranes studded with ribosomes that fold and modifies newly synthesized proteins

Gogli Apparatus

stacj of flattened membranes that modifies, sorts, and packages protiens and lipids for transportantion 

Ribosome

cellular structure made of RNA and protien that synthesizes protiens by translating genetic code 

Adenosine Triphosphate 

stores and prvides energy for cellular processes 

Model Organism 

non-human species that's studied in the lab to understand fundemental biological processes that apply to other organisms 

Orbital

region of space around an atomic nucleus where an electron is most likely to be found

Molecule 

a group of two or more atoms held together by chemical bonds 

Ionic Bond

formed when one atom transfers electrons to another

Covalent Bond

when two atoms share one or more pairs of valence electrons 

Hydrogen Bond

weak attraction between a partially positive hyrodgen atom and a partially negitive atom on another molecule or region 

Polar 

molecule/bond with an uneven distrubution of electrical charge; Hydrophilic 

Nonpolar

molecule/bond with an even distrubution of electrical charge; hydrophobic

Organic Molecule 

a carbon-based biological molecule 

Amino Acid

organic monomer molecules with an amino and carboxyl group that link together via peptide bonds to form functional protein polymers 

Carbohydrates 

organic molecules that serve as an energy source and structural component 

Nucleotides 

consists of a sugar, nitrogenous base, and phosphate groups

Nucleosides 

made up of sugar and nitrogenous base 

Monosaccharides

the simplest form of carbohydrates consisting of a single sugar monomer 

Disaccharides

carbohydrates formed when two monosaccharides are linked together by a glycosidic bond 

Polysaccharide 

complex carbohydrates compased of long chains of monosaccharide monomers linked together 

Glycosidic Bonds

a covalent bond formed between two carbohydrate/sugar molecules via a dehydration of synthesis reaction 

Phosphodiester Bond 

a covalent bond linking the 3' carbon of one sugar to the 5' carbon of another via phosphate group to form the nucelic acid backbone

Peptide bond

covalent bond formed between the carboxyl group of one amino acid and the amino group of another during protein synthesis 

Fatty Acid

A molecule consisting of a long hydrocarbon chain attached to a terminal carboxyl group 

Lipids 

a diverse group of hydrophobic organic molecules that store energy and form cell membranes 

Triacylglycerol

lipid-lipd molecule composed of a glycerol backbone attached to three fatty acid tails; used as the primary energy storage 

Glycerol

A three-carbon alcohol molecule that serves as the structural backbone for triacylglycerols and phospholipids 

Amphipathic Lipids 

lipid molecules that contain both hydrophilic regions and a hydrophobic region in the same structure 

Phospholipids 

Amaphipathic lipids consisting of a glyerol backbone, two hydrophobic fatty acid tails, and a hydropphilic phosphate group head 

Steroids

a class of lipids with a carbon skeleton consisting of four fused carbon rings 

Phospholipid bilayer 

two-layers sheet of phospholipid molecules with a hydrophilic head and hydrophobic tails 

Integral Membrane Protien

A protien permanetly embedded within the hydrophopic core of a biological membrane 

Peripheral Membrane Protein

 A protein temporarily attached to the exterior or interior surface of a membrane

Transmembrane Protein

An integral protein that spans across the lipid bilayer

Endomembrane System

network of internal membranes and organelles that work together to modify, package, and transport molecules

Passive Transport

Transporting substances across a cell membrane without ATP

Active Transport

Transporting sustances across a cell membrane with ATP 

Secondary Active Transport

Transporting sustances with electrochemical gradient created by primary active transport to move other substances

Channel Protein

Transmembrane protein forming an open pore, allowing specific molecules or ions to pass

Carrier Protien

Transmembrane protein that binds specific molecules and changes shape to shuttle them across

Diffusion

Net passive movement of particles from an area of high concentration to low concentration

Osmosis 

Passive diffusion of water across a selectively permeable membrane

Osmotic Pressure 

The pressure required to stop osmosis 

Isotonic 

A solution with the same solute concentration as the cell cytosol, resulting in no water movement

Hypotonic 

A solution with lower solute concentration than the cell cytosol, causing water to rush in

Hypertonic

A solution with higher solute concentration than the cell cytosol, causing water to rush out

Cernation

The shrinking & shriveling of an animal cell placed in a hypertonic solution

Plasmolysis

The pulling away of the plasma membrane from the cell wall in plant cells due to water loss

Symporter

A cotransporter protein that moves two different substances in the same direction

Antiporter

A cotransporter protein that moves two different substances in opposite directions

Electrochemical Gradient

The combined driving force of a concentration difference and electrical charge across a membrane

Exocytosis

 The process by which a cell exports large molecules by fusing vesicles with the plasma membrane

Phagocytosis

A form of endocytosis where a cell engulfs large solid particles

Pinocytosis

 A form of endocytosis where a cell engulfs extracellular fluid and dissolved solutes

Receptor Mediated Endocytosis

A targeted form of endocytosis where specific molecules bind to surface receptors to trigger vesicle formation

Deoxyribonucleic acid (DNA)

A double-stranded nucleic acid molecule that stores and transmits genetic information

Purines

adenine and  guanine; has two rings

Pyrimidines

cytosine, thymine, and uracil; has one ring

Base stacking

non-covalent, stabilizing interactions between adjacent base pairs stacked on top of one another inside the DNA core

Ribonucleic acid (RNA)

A single-stranded nucleic acid containing ribose sugar and uracil; essential for protein synthesis and gene regulation

Nucleotides

contains a sugar, base, and phosphate group

Nucleosides

contains only the sugar and base

Phosphodiester bond

The covalent chemical bond that links nucleotides together along the backbone of DNA and RNA strands

Hydrogen bonding

Weak bonds between complementary nitrogenous bases that hold the two strands of the DNA double helix together

Gene expression

The process by which information from a gene is used to direct the synthesis of a functional gene product (ex. protien)

RNA Polymerase

The core enzyme responsible for synthesizing an RNA strand from a DNA template strand during transcription

Promoter

A specific region of DNA, located near the start of a gene, where RNA polymerase and transcription factors bind to initiate transcription

TATA box

A conserved DNA sequence found in core promoters that helps position RNA polymerase

Sigma factor

A protein needed in bacteria to enable RNA polymerase to bind to specific promoters and initiate transcription

General transcription factors

Proteins in eukaryotes that bind to promoter sequences to help recruit RNA polymerase II and initiate transcription.

Transcriptional activator protein

A regulatory protein that binds to specific DNA sequences to boost the transcription of a gene

Primary transcript

The initial, unprocessed RNA molecule straight from transcription, containing both introns and exons.

RNA transcript

The freshly synthesized single strand of RNA produced by transcription from a DNA template

Messenger RNA (mRNA)

An RNA molecule that carries genetic information copied from DNA out of the nucleus to the ribosome for translation

Polycistronic mRNA

An mRNA molecule that encodes multiple different polypeptide chains

RNA processing

The modifications made to a primary eukaryotic RNA transcript before it becomes mature mRNA