question

Which of the following molecules is polar? CH3H7OH or C2H5COOH

answer

They are both polar.

question

Which of the functional groups affects the expression of genes when bound to DNA or on proteins bound to DNA?

answer

Methyl

question

A compound contains hydroxyl groups as its predominant functional group. Therefore this compound... a.) lacks asymmetric carbon and is probably a fat or lipid b.) should dissolve in water c.) should dissolve in a nonpolar solvent d.)will not form hydrogen bonds with water

answer

C

question

In what way do testosterone and estradiol differ from each other?

answer

different functional groups @ same carbon skeleton

question

Which is a false statement concerning amino groups? a. are basic with respect to pH b. are found in amino acids c. contain nitrogen d. are nonpolar

answer

D

question

How common are the elements living systems are made out of?

answer

Living organisms are 96% (carbon, hydrogen, oxygen and nitrogen) 4%- (calcium, phosphorus, potassium and sulfur) other 20 elements are less than 1% Of 92 natural elements, 20-25% are essential (orgs need to live a healthy life)

question

Why do atoms bond?

answer

Atoms bond because their outer electron shell (valence shell) must be filled in order for an atom to be stable, this requires either giving or taking electrons, which requires bonding to another atom.

question

What causes molecular polarity?

answer

Polarity results from the uneven partial charge distribution between various atoms in a compound. Atoms, such as nitrogen, oxygen, and halogens, that are more electronegative have a tendency to have partial negative charges. Atoms, such as carbon and hydrogen, have a tendency to be more neutral or have partial positive charges. When you have a very electronegative (need for electrons) with one that's not so, you end up with a partial negative and positive charge

question

How does the type of bonds present in a substance influence the chemical and physical properties of that substance?

answer

ex: saturated fatty acids have no double bounds between carbons which lets them pack solidly at room temperatures, why they are usually solids (butter, lard) unsaturated fats: have some double bounds, which results in kinks and they cannot pack tightly, therefore are usually liquids (oils) Phospholipids- hydrophilic polar head with phosphate group and fatty acid tails= hydrophobic...membranes are hydrophobic and only allow certain molecules in

question

How do properties of water or sodium chloride show emergent properties?

answer

Water- Hydrogen bonds, the polarity of the bonds allows the molecules to form hydrogen bonds with each other.

question

What is cohesion?

answer

linking of "like" molecules, hydrogen bonds form between molecules...EN Oxygen with + H. (TO EACHOTHER)

question

What is adhesion?

answer

clinging of one substance to another...to another polar substance (use their very EN and + charge to cling)

question

What is transpiration?

answer

movement of water molecules up thin xylem tubes and evaporation from stomata in plants

question

Specific heat in Water-

answer

amount of heat required to raise or lower temp of substance by 1 C. Water has a high specific heat due to the H bonds, H is very attracted to the EN oxygen and it takes more E to break that bond

question

Water as the "universal solvent"

answer

substance that dissolves another substance w/ any other polar molecule...H attracts the - charge of other and O attracts +

question

NaCl emergent properties-

answer

Na is a metal and Cl is a poisonous gas, but together they make something we can eat.

question

Why are radioactive elements useful for the study of biological systems?

answer

bone scans, kidney scans, and others. Radioactive isotopes and radioactively labeled molecules are used as tracers to identify abnormal bodily processes. This is possible because some natural elements tend to concentrate in certain parts of the body: iodine in the thyroid, phosphorus in the bones, potassium in the muscles. When a patient is injected with a radioactive element, a special camera can take pictures of the internal workings of the organ.

question

Ionic bonds-

answer

two atoms attract valence elctrons unequally that the more EN atom steals the electron from the less EN atom ion is the result +/- charge

question

Covalent Bonds-

answer

valence electrons are shared by two atoms nonpolar---electrons shared equally polar---one atom has greater EN than other, ,unequal share. EN is slightly -, less EN is +

question

Hydrogen bonds-

answer

relatively weak form between partially pos charged H atoms and very strongly EN atom of another (N or O)

question

How do you identify if a substance has ionic or covalent bonds?

answer

nonmetal and metal = ionic, nonmetal + nonmetal = covalent

question

What causes radioactivity?

answer

Radioactivity is caused when an atom, for whatever reason, wants to give away some of its energy. It does this because it wants to shift from an unstable configuration to a more stable configuration. The energy that is released when the atom makes this shift is known as radioactivity.

question

"Expansion with freezing"-

answer

When ice freezes, it expands because the hydrogen bonds The fact that water expands upon freezing causes icebergs to float. The fact that water reaches a maximum density at about 4°C causes bodies of water to freeze on the top first. Then the further expansion as a part of the phase change keeps the ice floating with some 8% of its mass above the surface. The expansion during the phase change may be shown on a PvT surface, and contrasts with the contraction upon freezing of most substances. he expansion upon freezing comes from the fact that water crystallizes into an open hexagonal form. This hexagonal lattice contains more space than the liquid state.

question

Ice with living orgss

answer

Ice is less dense than water, and therefore floats...this way organisms can live in the oceans without freezing

question

Relationship between disassociation of Water an pH

answer

When water dissassociates, it's when an H from one H20 attaches to another...makes H30 (hydronium) and leaves OH-. Acid is anything that increases the H, Base is anything that decreases. pH=-log [ H+]

question

Why is carbon central to the structure of all biological molecules?

answer

It has 4 valence electrons form 4 bonds single or double covalent bonds

question

What are isomers?

answer

molecules with same molecular formula but diff arrangement as number C increases, so does # isomers

question

Hydroxyl group-

answer

-OH polar bonds, H bonds alcohols like ethanol and methanol helps dissolve molecules like sugars

question

Carboxyl group-

answer

-COOH carboxylic acids such as fatty acids and suugars acidic properties because it tends to ionize; source of H ions

question

Carbonyl group-

answer

CO ketones and aldehydes like sugars

question

amino group-

answer

NH2 amines like amino acids

question

Phosphate-

answer

PO3 organic phosphates, including ATP, DNA and phospholipids

question

Sulfhydryl group

answer

SH found in some amino acids froms disulfide bridges in proteins

question

Methyl group-

answer

addition of a methyl group affects expression of genes

question

Why is carbon so great?

answer

ABUNDANT VERSATILE--double bonds, covalent and polar bonds bonds to self and others 4 bonds

question

Structural Isomers-

answer

same formula, different order

question

Cis-trans Isomers-

answer

same formula, different positioning around double bond

question

Enantiomers Isomers-

answer

same formula, mirror image position around central carbon atom

question

Why does the carboxyl group make something acidic?

answer

because it donates H

question

Why does amino group act as a base?

answer

Because it picks up Hs from surround

question

What is the amount of change in chemical structure to have a major effect on an living organism?

answer

in boys and girls, the testosterone and estradiol hormones just have a difference of ONE FUNCTIONAL GROUP

question

Why do biological systems use L amino acids and D sugars?

answer

more favored..natural selection favored these more...better

question

Explain the difference between a pH of 8 and a pH of 12, in terms of H conc.

answer

8- conc is lower 12- higher

question

How are macromolecules assembled from monomoers? broken down?

answer

assembled-dehydration reactions, two monomers joined by removing one water molecule broken down- hydrolysis, water is added to split up molecules

question

How can you tell if a biological molecule is a carbohydrate?

answer

include simple sugars and polymers like starch in ratio of 1carbon: 2hydrogen: 1 oxygen

question

Explain relationship between monosaccharides, disaccharides and polysaccharides, please and thank ya

answer

monosachh-(simple sugars) monomers of carbs (glucose and ribose) polysacch- polymers of monosacch (starch, cellulose and glycogen) disaccharide- 2 simple sugars or monosacch, formed by glycosidic linkage (cov bond) between two mono, by dehydrat synthesis to form.

question

Why are starch and glycogen useful as energy storage molecules, while cellulose is useful for structure and support?

answer

glycogen- stored in liver and muscle cells, hydrolysis of glycogen releases glucuse when demand for sugar increases starch- polymer of glucose monomers, stock pile for energy, later withdrawn from back cellulose-polymer of glucose, stronger and used for cell walls.

question

Why isn't cellulose easily broken down?

answer

we don't have correct enzymes to break down we have starch enzyme, therefore...can't have cellulose cows have it...cellulose digesting prokaryotes and protists in their gut..hydrolyze cellulose and convert it to glucose or other things for nourishment

question

How can you tell a biological molecule is a lipid?

answer

glycerol and three fatty acids fatty acids=hydrocarbon tail, non polar saturated--no double bonds unsat=double bonds phospholipids=hydrophil polar head, with phosphate group, two HC tails

question

Starch and Cellulose

answer

both composed of glucose monomers different ring forms and linkages---> diff functions we digest starch 1-4 alpha not cellulose 1-4 beta

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