Unit 2 - Molecules

Question 0

Hydrogen bonds

Answer 0

Weak bonds that form between the slightly neg. end and the slightly pos. end of two molecules. PLAYS A BIG ROLE IN BIOLOGY

Question 1

When do polar covalent bonds occur?

Answer 1

When one nucleus has a slightly positive charge (larger nucleus attracts electrons more strongly so it develops a slightly neg. charge while the smaller nucleus has a slightly pos. charge)

Question 2

Tell me about water

Answer 2

It’s a polar covalent molecule, it forms hydrogen bonds with itself (cohesion), it’s essential for life, and ice floats (it’s less dense than water)

Question 3

What 6 biologically important functions does water perform?

Answer 3

1. Regulates body temperature (has a high heat capacity) 2. Universal solvent (dissolves ionic + polar substances) 3. Transport medium (solutes, heat, etc) 4. Lubricant (joints) 5. Ampiphrotic (acts as both acid/base) 6. Cohesion/ Adhesion

Question 4

Acid

Answer 4

Any substance which releases H+ when it dissociates (pH 0-7)

Question 5

Base

Answer 5

Any substance which releases OH+ when it dissociates (pH 7-14)

Question 6

Substances which resist small changes in pH

Answer 6

Buffers

Question 7

Most biological systems require a pH scale near _____

Answer 7

Neutral (Ex. Blood : pH 7.4, a pH of 7.8 is fatal)

Question 8

Oxidation

Answer 8

The loss of electrons or hydrogen atoms in a reaction (An element that loses electrons or H+ in a chemical reaction has been “oxidized”)

Question 9

Reduction

Answer 9

The gain of electrons or H+ atoms in a reaction (The reactant which had gained atoms or H+ atoms has been “reduced”)

Question 10

Another way to say natural selection

Answer 10

Differential survival

Question 11

Polar covalent bonds must be _____ (structure/shape)

Answer 11

Asymmetrical

Question 12

What 4 elements make up 99% of the mass of most cells?

Answer 12

C,H,O,N

Question 13

The 4 levels of biomolecules

Answer 13

LEVEL 4: cell + organelles LEVEL 3: supramolecular complexes (chromosome, cell wall, plasma membrane) LEVEL 2: macromolecules (DNA, protein, cellulose) LEVEL 1: mononumeric units (nucleotides, amino acids, sugars)

Question 14

3 cellular uses of biological molecules

Answer 14

Anabolism, catabolism, enzymes

Question 15

Anabolism

Answer 15

When molecules are joined together to form a larger molecule, results in loss of water (BY DEHYDRATION SYNTHESIS)

Question 16

Catabolism

Answer 16

when a molecule is broken down into two or more smaller molecules, results in addition of water (BY HYDROLYSIS)

Question 17

Enzymes

Answer 17

A special class of proteins that speed up and initiate all chemical reactions in cells

Question 18

Draw dehydration synthesis

Answer 18

Question 19

Draw hydrolysis

Answer 19

Question 20

What is an organic compound

Answer 20

A compound (that makes up living things) that consists of carbon and hydrogen atoms covalent my bonded to each other + other elements (CAN BE CALLED HYDROCARBONS) (Can form polymers by joining monomers)

Question 21

What are the four groups of organic compounds

Answer 21

• carbohydrates - lipids - proteins - nucleic acids

Question 22

What can Carbon do that makes it so essential (in organic compounds)

Answer 22

• form covalent bonds to as many as four other atoms - rotate freely around a single covalent bond - form a variety of structures

Question 23

What’s a functional group

Answer 23

Atoms or groups of atoms that are attached to carbon backbones (provide distinct properties, such as solubility and chemical reactivity)

Question 24

Name and draw the four functional groups we have to know

Answer 24

1. HYDROXYL (-OH) 2. CARBOXYL (-COOH) 3. AMINE (-NH2) 4. PHOSPHATE (-H2PO4)