BIO 121 - Exam 1: Nature of Science, Chemistry of Life & the Cell

What are the five unifying themes of Biology?

Organization, Information, Energy and Matter, System Interactions, Evolution

What is the core theme of Biology?

Evolution

What does evolution account for?

unity and diversity of life

What are emergent properties?

New properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases.

What is gene expression?

the way in which DNA, RNA, and proteins are involved in putting genetic information into action in living cells

What is transcription?

The process of making RNA from DNA

What is translation?

RNA to protein

What is a hypothesis?

a testable prediction

What is a prediction?

A logical statement about what will happen in an experiment if the hypothesis is supported.

What is an independent variable?

factor in an experiment that a scientist purposely changes

What is a dependent variable?

variable that is measured

What is a control variable?

variable that stays the same

What is a control group?

The group that does not receive the experimental treatment in an experiment.

What is a theory?

well-tested explanation that unifies a broad range of observations

What is matter?

Anything that has mass and takes up space

What is an element?

a Substance that contains only ONE type of atom and cannot be broken down into simpler pieces

What is a compound?

two or more elements chemically combined

What is a proton?

positively charged particle (+1) found in the nucleus, determines element's identity

What is a neutron?

a particle that has no charge and that is inside the nucleus

What is an electron?

negatively charged particle (-1)

What is the atomic number?

the number of protons in an atom

What is the mass number?

the total number of protons and neutrons in a nucleus.

What do groups in the periodic table represent?

Columns containing elements with the same number of outer electrons.

What do periods in the periodic table represent?

horizontal rows representing number of electron shells

What are valence electrons?

Electrons in the outermost shell of an atom.

Why are valence electrons important?

They are involved in bonding; determine the reactivity of an element.

What does a full outer shell do for an atom?

Full outer shells often make atoms more stable

What is a covalent bond?

A chemical bond formed when two or atoms share electrons.

What is a nonpolar covalent bond?

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

What is a polar covalent bond?

A covalent bond in which electrons are not shared equally

What is an ionic bond?

A chemical bond that's formed when an atom transfers and electron to another Atom

What is a hydrogen bond?

the attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

What are water's emergent properties?

Polarity, hydrogen bonding, cohesion, adhesion, surface tension, high specific heat, high heat of vaporization, ice is less dense than liquid water, excellent solvent

What is an acid?

An acid is a source of hydrogen ions, H⁺

What is a base?

a substance that reduces the hydrogen ion concentration of a solution (OH-)

What is the pH scale?

measures how acidic or basic a substance is

What does each unit change represent on the pH scale?

10x change in H+ concentration

What is the Miller-Urey experiment?

a chemical experiment that simulated the conditions thought at the time to be present on the early Earth, and tested the chemical origin of life under those conditions.

What makes carbon so important in biological molecules?

Has 4 valence electrons and is able to form 4 covalent bonds total; can form single, double, and triple bonds, chains, rings, and branched structures

What is an isomer?

Compound with same atoms, but arranged differently

What is a structural isomer?

Compounds with the same molecular formula but different structural formula

What is a cis-trans isomer?

They have the same covalent bonds but differ in spatial arrangements

What is an enantiomer?

each of a pair of molecules that are mirror images of each other (not superimposable)

What is a functional group?

a group of atoms responsible for the characteristic reactions of a particular compound.

What is a hydroxyl group?

a hydrogen bonded to an oxygen (-OH)

What is a carbonyl group?

Carbon double bonded to an oxygen (C=O)

What is a carboxyl group?

a carbon double-bonded to both an oxygen and a hydroxyl group (-COOH)

What is an amino group?

functional group that consists of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of these three (-NH2)

What is a sulfhydryl group?

sulfur bonded to hydrogen (-SH)

What is a phosphate group?

a phosphorus atom bonded to four oxygen atoms (-PO4)

What is a methyl group?

carbon bonded to 3 hydrogens (-CH3)

What are the four major macromolecules?

carbohydrates, lipids, proteins, nucleic acids

What is a carbohydrate?

compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body

What are carbohydrates built from?

monosaccharides

How are carbohydrates bonded?

glycosidic linkage

What is a lipid?

A biological molecule with low solubility in water, long term energy storage, hormones/signaling

What are lipids built from?

fatty acids and glycerol

How are lipids bonded?

ester linkage

What is a protein?

sequence of amino acids used in enzyme transport, structure, defense, movement, and signaling

What are proteins bonded by?

peptide bonds

What are nucleic acids?

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus

What are nucleic acids made of?

nucleotides

How are nucleic acids bonded?

phosphodiester bonds

What is dehydration synthesis?

the process of joining two molecules, or compounds, together following the removal of water

What is hydrolysis?

the separation of two macromolecules by adding water.

What is a saturated fat?

a type of fat with no carbon-to-carbon double bonds, straight chains, and are usually solid at room temperature (contain more hydrogen)

What is an unsaturated fat?

fatty acids that contain one or more carbon-to-carbon double bonds and are more commonly found in plant oils and are known to be a healthier fat. usually liquid at room temperature

What is the primary structure of a protein?

sequence of amino acids

What is the secondary structure of a protein?

Twisting of the alpha helix, Beta pleated sheets, Hydrogen bonding

What is the tertiary structure of a protein?

folding of a polypeptide chain due to interactions between side chains of amino acids that lie in different regions of the primary sequence

What is the quaternary structure of a protein?

interactions between different polypeptide chains in proteins composed of more than one polypeptide (subunit interaction)

What is DNA?

deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

What is RNA?

ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.

What is the cell membrane?

the semipermeable membrane surrounding the cytoplasm of a cell.

What is a phospholipid?

It is a lipid that has a phosphate group attached to the glycerol and only two fatty acid chains.

What is the phospholipid bilayer?

a two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward.

What part of the phospholipid is hydrophobic?

fatty acid tails

What part of the phospholipid is hydrophilic?

phosphate head

What is the fluid mosaic model?

describes the arrangement of the molecules that make up a cell membrane

What are the components of the fluid mosaic model?

phospholipids, cholesterol, proteins, carbohydrates

What is a membrane protein>

a protein molecule that is attached to, or associated with the membrane of a cell or an organelle

What is selective permeability?

ability of a membrane to regulate passage of materials into and out of the cell (small non polar molecules can usually cross more easily, large/charged/strongly nonpolar molecules usually need assistance from a protein)

What is passive transport?

The movement of materials across the cell membrane without using cellular energy

What is simple diffusion?

when molecules spread from an area of high to an area of low concentration

What is facilitated diffusion?

Movement of specific molecules across cell membranes through protein channels

What is osmosis?

diffusion of water across a selectively permeable membrane

What is active transport?

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.

What is tonicty?

the ability of a solution to cause a cell to gain or lose water

What is a hypertonic solution?

The solution has a higher solute concentration than the cell so water moves out of the cell and into the solution causing the cell to plasmolyze

What is a hypotonic solution?

the solution has a lower solute concentration than the cell so water moves into the cell causing plant cells to swell and animal cells to swell and burst

What is an isotonic solution?

Contains equal concentratinos of solutes on both sides.

What is bulk transport?

the transport of very large molecules in and out of the cell

What is endocytosis?

process by which the cell takes in materials that are too large to pass through

What is exocytosis?

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

What is a prokaryotic cell?

cell that does not have a nucleus or organelles

What is a eukaryotic cell?

Cell with a nucleus and membrane bound organelles

What is a organelle?

A tiny cell structure that carries out a specific function within the cell

What is the nucleus?

Control center of the cell, stores DNA

What do all cells have?

plasma membrane, cytoplasm, DNA, ribosomes

What is a ribosome?

site of protein synthesis