Cell Bio Exam 1

Gene

A segment of DNA that contains the information required to produce a product that functions in the organism.

Alleles

Different versions of a gene that have slight variations in the DNA sequence found in other alleles of the same gene. 

Transcription

The process that creates an RNA molecule from information stored in a gene.

Translation

The process that uses the information in messenger RNA (mRNA) to synthesize a protein.

metabolism

The chemical reactions and other processes that enable organisms to take in resources and process them in ways that make growth and reproduction possible.

Chromosome

A DNA molecule — circular or linear, depending on the species — usually associated with specific proteins that bind to the DNA.

Ribosome

A molecular machine consisting of RNA and proteins that is the site of protein synthesis.

Cytoskeleton

Rod-like proteins inside cells that function in structural support, transport of materials, and movement in some species.

Nucleus

An organelle unique to eukaryotes enclosed by a double membrane and containing the cell’s chromosomes.

Vacuole

An organelle that stores key molecules; very prominent in most plant cells.

Chloroplast

An organelle that contains the molecular machinery required for photosynthesis.

Endoplasmic reticulum (ER)

The place where proteins, membrane lipids, and other molecules are synthesized and/or processed.

Golgi

An organelle comprised of stacked, flattened sacs, where proteins and other molecules are processed and packaged for shipment to specific destinations.

Actin filaments

Small-diameter cytoskeletal fibers made of subunits of the protein actin.

Intermediate filaments

Cytoskeletal fibers whose size is intermediate between those of actin filaments and microtubules and can be made from a variety of protein subunits.

Microtubules

Large-diameter, hollow cytoskeletal elements made of pairs of the proteins α-tubulin and β-tubulin.

Nuclear envelope

composed of inner and outer membranes and contains pores

Mitochondrial structure

inner and outer membrane and foldings called Cristae

Which organelle has its own DNA and ribosomes

mitochondria

Thylakoids

flattened membranous sacs found in chloroplasts

Smooth ER

synthesizes fatty acids, phospholipids, and cholesterol. NO role in protein synthesis

rough ER

synthesizes proteins

The golgi apparatus

“shipping and receiving center”, sorts and packages materials into transport vesicles

exocytosis

when vesicles carry materials to be exported from the cell

endocytosis

when vesicles bring material into the celll

Lysosomes

helps digest and destroy old substances/waste within the cell. attaches to food vacuoles

Which parts of the cytoskeleton enable movement?

microtubules and actin filaments

which parts of the cytoskeleton are found only in some animal cells and provide support?

Intermediate filaments

Element

A distinct type of substance or matter. Each element has atoms that contain a unique number of protons in the nucleus.

Atom

The fundamental unit of an element, made of protons, neutrons, and electrons.

Electronegativity

The tendency for an atom's nucleus to attract the shared electrons in a covalent bond.

Polar covalent bond

An asymmetry in the position of shared electrons, due to differences in the electronegativities of the atoms involved, that creates a partial positive charge on one atom and a partial negative charge on the second atom.

Nonpolar covalent bond

Equal sharing of electrons, due to equal or roughly equal electronegativities of the atoms involved.

Hydrogen bond

An attraction between a partial positive charge on a hydrogen atom and a partial negative charge on another atom.

Hydrophilic molecule

a molecule that can readily interact with the partial charges on water.

Hydrophobic molecule

a molecule that contains mostly nonpolar covalent bonds and cannot readily interact with the partial charges on water.

Ion

an atom or molecule that carries a full charge. 

Acid

an ion or molecule that releases a proton (H⁺). 

Base

an ion or molecule that acquires a proton (H⁺).

Van der waal forces

weak attractions between two atoms that occur only if the atoms are very close to one another and oriented appropriately

Solvent

a fluid in which another substance can dissolve

Lipid

A molecule that does not dissolve in water.

Saturated

A hydrocarbon chain that contain only single bonds.

Unsaturated

A hydrocarbon chain that contains one or more double bonds.

Fat

A lipid comprised of three fatty acids—these are hydrocarbon chains with a COOH group on one end—attached to glycerol (a 3-carbon compound).

Steroid

A lipid containing a specific "four-fused-rings" structure.

Phospholipid

A lipid that consists of 1) a hydrophilic "head" that includes a phosphate group and another polar group, and 2) a hydrophobic hydrocarbon tail.

Amphipathic

A molecule having both a hydrophobic region and a hydrophilic region.

Monosaccharide

an organic molecule that includes a carbon chain, a C=O group, and C-OH groups. The carbon chain can be linear or form a ring structure. Also called a simple sugar.

Glycosidic linkage

a covalent bond that links monosaccharides together to form polymers.

Glycan

a polymer made up of many monosaccharides joined by glycosidic linkages. (Synonymous with 'polysaccharide.')

Carbohydrates

a family of molecules that includes both monosaccharides and glycans.

Four major classes of macromolecules

1. Lipids

2. Carbohydrates

3. Nucleic acids

4. proteins

Functional groups

groups of atoms that give specific properties to the molecules in which they belong

hydrogen bonds

how functional groups interact

Seven biologically important functional groups

• Hydroxyl group

• methyl group

• carbonyl group

• carboxyl group

• amino group

• phosphate group

• sulfhydryl group

Carbonyl group

c=o

carboxyl group

COOH

sulfhydryl group

-SH

Fatty Acid chain

unsaturated fatty acids

c=c bond causes a kink in the molecule

Triglycerides

glycerol molecule

Glycerol

three carbon alcohol with a hydroxy on each carbon

triglycerides function

energy storage

Phospholipid

glycolipid

lipids containing a carbohydrate instead of a phosphate group

Steroids

lipids characterized by a carbon skeleton consisting of four fused rings

Cholesterol

a type of steroid, precursor from which other steroids are synthesized non soluble in water ,

Van der Waals forces

____ between fatty acid tails hold membrane together

Isomer

molecules with identical molecular formulas but distinct arrangements of atoms

glycosidic bonds

two monosaccharides can be linked via ____ to form a disaccharide

condensation reactions

two molecules join together as a result of the loss of a water molecule

hydrolysis reaction

two molecules broken apart by a water molecule

Polysaccharides

polymers of sugars with storage and structural roles

Glycogen

storage polysaccharide in animals, glucose monomers

starch

storage polysaccharide in plants, glucose monomers

Chitin

structural polysaccharide found in insect exoskeletons and fungal cell walls. Conists of a derivative of glucose

cellulose

structural polysaccharide of plants, glucose monomers

aqueous, sugars form rings

in ____ solutions many ____

alpha D glucose

hydroxyl group downward

beta D glucose

hydroxyl group upwards

ribose

five carbon sugar found in RNA

deoxyribose

five carbon sugar found in DNA

nucleotide

nucleoside

the portion of a nucleotide without the phosphate group

monophosphate

one phosphate group (NMP, dNMP)

diphosphate

two phosphate groups (NDP, dNMP)

triphosphate

three phosphate groups (NTP, dNTP)

Nucleotide

A molecule made up of a phosphate group and a nitrogenous base bonded to a 5-carbon sugar.

Phosphodiester bond

 Covalent bonds between the phosphate group on the 5′ carbon of one nucleotide and the -OH group on the 3′ carbon of a second nucleotide.

Complementary base pairing

Hydrogen bonding between A-T or A-U and G-C pairs in a nucleic acid.

Primary structure

The sequence of nucleotides in a nucleic acid, read 5′ to 3′.

Secondary structure

Formation of a double helix in DNA or a stem-and-loop structure in RNA, based on complementary base pairing.

Sugar-phosphate backbone

The "spine" of 5-carbon sugars and phosphate groups in a nucleic acid (the nitrogenous bases project from this backbone).

Antiparallel strands

Strands of DNA or RNA that align in opposite 5′ to 3′orientation.

Monomer

A small "subunit" molecule that can be linked to another, via a covalent bond, to form a larger molecule called a polymer.

Polymer

A large molecule made up of strings of covalently bonded small molecules (monomers).

Amino acids

the building blocks that connect together via covalent bonds to form proteins

Amino group

a group of NH₂ atoms; can pick up a proton to form NH₃⁺

Carboxyl group

a group of COOH atoms; can lose a proton to form COO^-