Bio 172 Exam 1 University of Michigan

Cell

lowest level in hierarchy of biological organization

stores & transmits information

Theory of Evolution

All species are related by decent from a common ancestor

Tree of Life

A diagram depicting the genealogical relationships of all living organisms on Earth, with a single ancestral species at the base.

Archea

Domain of prokaryotic organisms that are biochemically and genetically distinct from bacteria.

Eukaryotes

Cells that contain nuclei

Prokaryotes

Cells that do not contain nuclei

Cell Theory

1) Cells are structural units of life

2) Cells are the functional unit of life

3) All cells are fundamentally similar. Specific cell functions vary

4) All cells come from pre-existing cells

Hypothesis

Testable statement

Theory

explanation that is well-substantiated and can incorporate facts, laws, inferences, and tested hypotheses

Scientific Method

A series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.

Protons

Have a positive charge

Atomic number

Found in nucleus

Contributes to atomic mass

Neutrons

Has a neutral charge

Found in nucleus

Contributes to atomic mass

Electron

Negative charge

Found in clouds/orbitals

Mass number

the sum of the number of neutrons and protons in an atomic nucleus

Valence

The electrons in the outermost shell (main energy level) of an atom; these are the electrons involved in forming bonds.

Covalent bond

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

Nonpolar covalent bond

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.

Polar covalent bond

A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

Hydrogen Bond

A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.

Ionic Bond

A chemical bond resulting from the attraction between oppositely charged ions.

Cation

Positive Ion

Anion

Negative Ion

Van der Waals

A slight attraction that develops between the oppositely charged regions of nearby molecules.

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

Liquid

No crystal lattice forms in this form of H2O

Polar molecules/Ions

Dissolve readily in H2O

Nonpolar molecules

Do not dissolve readily in H2O

Observation

Act of viewing the world around us

Experimentation

Disciplined and controlled way of asking and answering questions about the world in an unbiased manner

DNA

A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins.

Easily replicated

RNA

A single-stranded nucleic acid that passes along genetic messages

Transcription

(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA

Translation

(genetics) the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm

Central Dogma

DNA -> RNA -> Protein

gene

A segment of DNA on a chromosome that codes for a specific trait

Mutation

(genetics) any event that changes genetic structure

plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Separates living/nonliving material

Nucleus

houses DNA

large & highly organized

structure: surrounded by a double-membrane nuclear envelope

function: information storage & processing

contains chromosomes

where RNA transcription occurs

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

metabolism

All of the chemical reactions that cells use to convert energy from one form to another

Evolution

change over time

environmental variation

due to differences in the environment

genetic variation

differences in the genes that are transmitted from parents to their offspring

Ecology

the study of how organisms interact with one another and with their physical environment in nature

Atom

fundamental unit of matter

Molecules

Chemicals that result from atoms linking together

Chemical bonds

Forces that hold atoms or ions together in a compound

Water

_____ is a polar molecule

Structure of an amino acid

carbon atom (Alpha C) attached to a carboxyl group, an amino group, H, and a side chain (R group)

R group

determines the properties of each amino acid

nucleotide

A subunit of nucleic acid formed from a simple sugar, a phosphate group, and a nitrogenous base.

Pyrimidines

Thymine

Cytosine

Uracil

Purines

adenine

guanine

energy

the capacity to do work

# of amino acids

20

hydrophilic

interacts with water

hydrophobic

does not interact with water

polypeptide

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

peptide bond

bond formed between amino acids in a polypeptide

condensation reaction

reaction that produces H2O

peptide bonds are this type of reaction

primary structure

linear sequence of amino acids held together by covalent (peptide) bonds between amino acids

Alpha Carbon

Has four groups bonded to it; R side chain, amino group, carboxyl group, and hydrogen , refers to the first carbon that attaches to a functional group

secondary structure

interactions between atoms in the backbone

H bonds between the carboxyl group of 1 amino acid & the amino group of another form this structure

alpha helices

coiled secondary structure

beta pleated sheets

folded secondary structure

Tertiary structure

overall 3D shape of polypeptide

held together by interactions between R groups

Determinants of protein structure

cell environment

temperature

pH

salts

Quaternary Structure

the shape resulting from the association of two or more polypeptide subunits.

denaturization

loss of protein conformation

promoted by heat, pH change, chemicals

renaturization

The process of a protein returning to its original configuration and function.

potential energy

stored energy

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration. From area of high free energy to low free energy

substrates

- the molecule upon which an enzyme acts

substrate

enzymes are _________ specific.

phosphate groups

In ATP high energy bonds present between what?

less

____ disorder = more chemical energy in bonds

reaction rate

rate at which reactants change into products over time

ionic Hydrogen Van der Waals

Bonds between substrate and enzyme

can affect reaction rate

substrate concentration

enzyme concentration

temperature

pH

DNA structure

2 strands of nucleotides in a double helix

strands oriented in opposite directions (antiparallel)

bases point inside the helix (sugar-phosphate outside)

opposing bases "pair" by H bonding

Purine-Pyrimidine

Only _____-_________ pairs fit inside the double helix

%Guanine

%Cytosine=

%Adenine

%Thymine=

phosphodiester bonds

strong, covalent linkages formed by a condensation reaction between the 3′-hydroxyl group of one nucleotide sugar and the 5′-phosphate group of another

Fatty acid

Building Blocks of Lipids

Hydrocarbon chains with terminal carboxyl group

may be saturated or unsaturated

NOT water soluable

saturated fats

no double bonds

solid at room temperature

unsaturated fats

has double bonds

liquid at room temperature

double bonds create kinks in the chains

glycerol

can link to fatty acids

synthesis

condensation (dehydration) reaction

Ester linkage

link between glycerol and fatty acid

phospholipid

A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

lipid

diverse group of water-insoluble, hydrophobic organic compounds (fats, oils, waxes, steroids)

lipid bilayers

double layer of lipids arranged tail-to-tail; structural foundation of all cell membranes

cholestrol

__________ (a steroid) stabilizes the membrane

largely hydrophobic

20-30% of the bilayer should be made up of this substance

integral membrane proteins

proteins that are partially, or entirely, located within a membrane

peripheral membrane protein

part of the protein is outside of the lipid bilayer

Roles of proteins in membranes

transport in/out of the cell

reception of molecules

enzymes

anchor different parts of the cell

small nonpolar molecules

breeze through bilayer