Biology Midterm 2011

1.Observation

2.Form a hypothesis

• 3.Test the hypothesis by performing a controlled
• experiment

4.Record and analyze the results

5.State the conclusion

6.Replicate work

1)All living things are made of one or more cells

2)All living things reproduce

3)All living things contain genetic material

4)All living things grow and develop

5)All living things obtain and use energy

• 6)All living things respond to stimuli (their
• environment)

7)All living things maintain homeostasis

8)All living things evolve

smallest unit of matter

sum of the protons and neutrons

CHNOPS: carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur

• atoms of the same element with a different number of neutrons
• unstable isotopes are radioactive-gives off energy and throws off particles

valence electrons are transferred from one atom to another, causing each atom to have a charge

• Cation (positive)
• Anion (negative)

groups of atoms of more than one kind of element attached by covalent bonds

• two atoms share valence electrons so each atom has a complete outer shell
• stronger than an ionic bond

molecule with uneven charge distribution

• polar: formed due to unequal sharing of electrons between atoms
• non-polar: formed when sharing of electrons between atoms is equal

• exothermic- produces heat
• endothermic- requires heat

it can dissolve ionic compounds due to its polarity

• they are formed when the positive (hydrogen) end of one water molecule is attracted to the negative (oxygen) end of another water molecule
• individually they are not strong, but as a group they are

• 1. high heat capacity (large number of hydrogen bonds can absorb heat without a large change in temperature)
• 2. high heat of vaporization (large number of hydrogen bonds must be broken to evaporate water)
• 3. cohesive and adhesive (attracted to itself, attracted to other things)
• 4. high surface tension (frozen water is less dense than liquid water)

• Acids are substances that dissolve in water, releasing hydrogen ions (H+)
• Bases are substances that either take up hydrogen ions (H+) or release hydroxide ions (OH-)

• organic require carbon and hydrogen
• inorganic are held together by covalent bonds, and organic are held together by ionic bonds

specific combinations of bonded atoms that always react in the same manner, regardless of the particular carbon skeleton

organic molecules that have identical molecular formulas but a different arrangement of atoms

large molecules made by joining smaller units (monomers) together in long chains

• a chemical reaction joining monomers of organic compounds to make polymers
• opposite is hydrolysis

glyceraldehyde: C₃H₆O₃

• glucose
• ribose
• deoxyribose

• sucrose- glucose and fructose
• maltose- 2 glucose
• lactose- glucose and galactose

• starch
• cellulose
• chitin
• glycogen

• fats
• oils
• phospholipids
• waxes
• steroids
• *all lipids contain either hydrocarbon chains or fatty acids except steroids*

• long hydrocarbon chain
• carboxyl group (COOH/COO-)

one molecule of glycerol linked to one, two, or three fatty acids

• unsaturated contain at least one double bond between the carbons, which causes the fatty acid to bend and push apart instead of tightly stacking together, so it becomes fluid (oils)
• saturated contains no double bonds between the carbons, so it can stack easily and is a solid (fats)

• trans fat is unsaturated, but it can be stacked into a solid because the hydrogens are on opposite sides of the double-bonded carbons so they DON'T BEND
• cis fat is normal unsaturated fatty acids, where the hydrogens are on the same side so it bends

• made up of two fatty acids (at least one must be unsaturated), glycerol, and a phosphate group
• amphipathic: one side is hydrophobic (tails) and one is hydrophilic (heads)

• steroids have skeletons of 4 fused carbon rings
• cholesterol

• a long-chain fatty acid bonded with a long-chain alcohol
• 1. high melting point
• 2. waterproof
• 3. resistant to degradation because of length

• carry genetic information
• dictate the amino acid sequence of proteins to perform basic life processes

nucleotides (nitrogen base, sugar, phosphate) connected to form long chains

• DNA doesn't contain oxygen, while RNA does
• DNA is double stranded to form a double helix, while RNA is single stranded
• DNA stores genetic info, and RNA carries genetic info from the DNA

• DNA- adenine, guanine, cytosine, thymine
• RNA- adenine, guanine, cytosine, uracil

long chain of amino acids (polypeptide)

protein

amino group, carboxyl group, central carbon

a covalent bond connecting two amino acids

• 1. enzymes: helps reactions occur more easily
• 2. transport: moves nutrients/molecules
• 3. structure/support: supports structures in cells or tissues
• 4. defense: wards off disease and infection
• 5. hormones: serves as intercellular messages
• 6. motion: moves molecules or tissues

"building up" reactions, or synthesis

"breaking down" reactions, or decomposition

• catalysts for biological reactions
• they lower activation energy to speed up reactions

• can identify the reactant
• sucrase: cuts sucrose
• can describe its function
• oxidase: catalyzes oxidation

consists of all chemical activities and changes that take place continuously in a cell or organism

where the substrate (reactant) binds to the enzyme

• temperature
• pH
• substrate concentration
• activators/inhibitors

activators increase enzyme activity, and inhibitors decrease enzyme activity

• competitive: has a similar structure to substrate, binds to active site of enzyme
• non-competitive: doesn't have similar structure, binds to allosteric site which changes the shape of active site

when the enzyme's structure is altered