Life 102 Exam 1 CSU Arthun

At what organizational level is life's uniformity most evident?

Most evident in cells

At what organizational level is life diversity most evident?

Most evident in organisms

How do Atoms fill their Valence shell?

Donate or accept electrons from another atom or two atoms can share an electron pair creating a covalent bond.

What happens when an atom gains or loses an electron?

It becomes ionic

96% of living mater is composed of which elements?

Carbon, Nitrogen, Hydrogen, Oxygen (HONC)

How can you distinguish one element from another?

By the number of protons

What are isotopes?

Isotopes are the same element, with a different number of neutrons.

How do isotopes differ?

Based on their number of neutrons

What is a covalent bond?

A covalent bond is when two atoms share an electron pair

What is the difference between a polar and non-polar covalent bond?

Polar covalent bond electrons are not equally shared between the two atoms, non-polar are equally shared

How do atoms share a pair of electrons?

Through covalent bonds

What effect does the sharing of a pair of electrons have on their valence shells?

They can fill their valence shells

How many electrons does it take to fill the valence shells of C, H, O, N

Carbon-4

Nitrogen-3

Oxygen-2

Hydrogen-1

Why are hydrogen bonds important for biological molecules? Example of a biological molecule that contains hydrogen bonds

They are important because due to them water has a high heat of vaporization, it will cause a high specific heat as we. It is also important for giving stabilization without permanent bonds. DNA is an example of a biological molecule containing hydrogen bonds

What does mass conservation law state?

Mass can be changed from one form to another but the overall mass does not change (number of molecules doesn't change)

What does it mean when a reaction is reversible?

Because its a reaction that can go from reactants to products or products to reactants.

What is chemical equilibrium?

When the rate of the forward reaction is equal to the rate of the reverse reaction.

Why is water a polar molecule?

Because it has a partial negative charge and a partial positive charge because the oxygen is partially negatively charged and hydrogen is partially positive.

What type of bonds do water molecules form with each other?

Hydrogen bonds

What are the properties of water?

Cohesion, surface tension, high specific heat, heat of vaporization.

Cohesion

high surface tension

surface tension

measure of how hard it is to stretch/break the surface of a liquid

high specific heat

the amount of energy it takes for temperature to raise 1 degree

Heat of Vaporization

amount of energy it takes to go from a liquid to a gas

What is the density of water at various temperatures?

Water is frozen at 4 degrees celsius

Why does ice float?

Because water molecules are more spread out when frozen (expand)

How do hydrophilic and hydrophobic compounds interact with water?

Hydrophilic has high affinity for water ions (polar molecules), hydrophobic has low affinity for water ions (non polar molecules and non ionic elements)

What is concentration?

how much solute is present per volume of solvent in moles

What is solute?

substances that are dissolved

What is a solvent?

the dissolving agent of a solution

Why is water a good solvent?

Because it forms hydrogen bonds easily

What types of solutes dissolve in water?

Hydrophilic solutes

What pH range does an acidic solution have?

less than 7

What pH range does a basic solution have?

greater than 7

What pH range does a neutral solution have?

equal to 7

What does pH have to do with H+ concentration?

Acids have higher increase of H+, bases are any substances that reduce H+

What is the formula used to calculate pH?

For each change in pH by one unit, H+ changes 10 fold.

What is the pH of pure water?

7

How many H+ ions are in pure water

10^7-7M

Buffers

stabilize substance that minimizes changes in H+ ions, OH- ion stabilizes.

How does a base like KOH affect the H+ concentration in a solution

H+ bonds to the OH- forming water, all thats left is K+ and water.

Why is NH3 a base?

because is can react with a hydrogen ion

What is an organic molecule?

consists of proteins, acids, DNA, fats and sugar

What are the advantages of using carbon as a building block for organic molecules

carbon is tetravalent(can make 4 bonds), needs 4 electrons to fill valence shell, capable of making 4 chemical bonds, large complex and diverse molecules, accounts for the diversity of life on the planet

Variations in the carbon skeleton

Length, Branching, double bond position, presence of rings

What is the difference between 1-butene and 2-butene?

Its double bond postion

What is the difference between butane and isobutane?

Butane is unbranched, isobutane is branched

Hydroxyl groups

functions as polar

Carbonyl groups

functions as polar

Carboxyl

functions as acid

Amino groups

function as bases

Sulfhydryl groups

bid their sulfhydryl groups

Phosphate groups

function as polar reactive

Methyl groups

function as non-polar

Isomer

same atomic composition but different structures and properties

Structural Isomers

variation in covalent partners, as shown in example of butane and isobutane

Cis-trans isomers

variation in arrangement of side groups

Enantiomers

mirror images

What is the role of a dehydration synthesis reaction in the formation of a polymer?

removes a water molecule, forming a new bond

What does the hydrolysis reaction do to a polymer?

adds a water molecule, breaking a bond

Glucose forms a ring structure, what are the atoms that make up the ring?

5-Carbon and 6-carbon sugars form ring structures

What do you call two sugar monomers linked together?

Polysaccharides

What are the functions of polysaccharides?

Energy storage and support

What are lipids?

They arrant polymers, not as big an are hydrophobic

What are the components of a triglyceride (fat)?

glycerol+3 fatty acids

What are the components of a phospholipid and why do these molecules spontaneously form bilayers in water?

Hydrophilic head + 2 hydrophobic tails. Because tails are hydrophobic

What are saturated and unsaturated fats and how can they be distinguished at room temperature?

Saturated fats are solid at room temperature and have double bonds. Unsaturated fats are liquid at room temperature and do not have double bonds

How can you recognize the chemical structure of an amino acid?

Peptide Bonds

The 20 essential amino acids are classified as being non-polar, polar and electrically charged. What does that mean?

Depending on side group (R)

What is a peptide bond?

bonds that like individual amino acids

What is a dehydration synthesis reaction?

reaction that removes water molecule forming a new bond

What determines the shape of a protein?

the primary structure

Primary Structure of a protein

series of amino acids that are peptide bonded to each other "string of pearls"

Secondary Structure of a protein

folds and bends

Tertiary structure of a protein

3D structure

Quaternary Structure of a protein

two territory put together (Hemoglobin)

How is the 3D shape of a protein stabilized?

Hydrogen bonds, disulfide brides, and ionic bonds

Hydrogen Bonds

non-polar covalent bonds in side groups, can't interact with polar molecuels

What is protein denaturation?

loss of protein conformation

Is a denatured protein still functional?

Not still functional because it lost its shape

What are some examples of protein functions?

Enzymes, antibodies, structural proteins, contractile porteins, transport, communication

What are the components of a nucleotide?

Have a phosphate group, sugar, nitrogenous bases

How are nucleotides arrangedto form DNA or RNA?

A-T C-G

Which part of the nucleotide molecule is the backbone?

Phosphates

What are the differences between DNA and RNA?

DNA directs synthesis of messenger RNA (mRNA) and through mRNA controls protein synthesis

What rules govern base pairing

Purine always base pairs with a Pyramidine

DNA strands are described as being complementary and anti-parallel. What does that mean?

It means they are opposite of each other

What are the differences between prokaryotic and eukaryotic cells?

The domains Bacteria and Archaea consist of prokaryotic cells. Protists, fungi, animals, and plants all consist of eukaryotic cells. Eukaryotic cells are characterized by having: DNA in a nucleus that is bounded by membranous nuclear envelope, membrane bound organelles, and cytoplasm in the region between the plasma membrane and nucleus. Prokaryotes have no nucleus and no membrane bound organelles.

Why are eukaryotic cells compartmentalized? What is the advantage of compartmentalization?

Because there are many specialized cell compartments. Advantage is their is an increased division of labor.

What is the structure of the nuclear envelope? What are nuclear pore complexes?

Double membrane surrounding nucleus. Pore complexes connects nucleus to cytoplasm and serve as a selective passage between nucleus and cytoplasm

What is the function of ribosomes? Where are they located?

Carry out the instructions with the aid of certain RNA molecules, most are free in the cytosol some are bound to the ER or nuclear membrane.

What is rough and smooth endoplasmic reticulum? Which classes of molecules are synthesized in the rough and the smooth endoplasmic reticulum?

Rough ER: studded with Ribosomes

Smooth ER: no ribosomes

Ribosomes are synthesizes

What is the structure and function of the Golgi apparatus? Where do proteins go from the Golgi?

stacks of flattened membrane sacs; ships proteins off to the plasma membrane

How are cell contents moved from one location to another (i.e. from ER to Golgi)?

Via Vesicles; vesicles can bud off one membrane and fuse with another->contents transported

What is the function of lysosomes and vacuoles?

Lysosomes are the digestive Enzyme Vesicles;digestion of food particles and damaged organelles. Vacuoles are large ER/Golgi derived vesicles, for sturdiness and storage of: ions, metabolites, pigments and toxins

Why are lysosome contents separated from the cytoplasm?

What is the endomembrane system in cells?

system that regulates protein traffic and performs metabolic functions

Which organelles are not part of the endomembrane system?

Mitochondria, Chloroplasts, and Peroxisomes

What is the structure and function of mitochondria?

Mitochondria have a smooth outer membrane and an inner membrane folded into crust. The inner membrane creates two compartments: inter membrane space and mitochondrial matrix. Some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix. Cristae present a large surface area for enzymes that synthesize ATP. Mitochondria functions to convert chemical energy and energy production via "respiration" sugar+O2->CO2+H2O+energy.

What is the endosymbiont theory?

derived from Prokaryotes-ncorporated into larger host cell