Honors Biology: Cumulative Assessment 1

What do all living things have in common?

1. made up of cells

2. contain DNA

3. grow and develop

4. need food for energy

5. reproduce

6. respond to stimuli

7. populations evolve

What are the 8 life processes and what they are?

1. Cellular Respiration: process that releases energy from food (w & w/o O₂)

2. Excretion: removal of toxic waste

3. Regulation: communication between systems that helps maintain homeostasis

4. Reproduction: continues species (sexually & asexually)

5. Transport: movement of materials throughout organism

6. Synthesis: combination of simple substances to form more complex substances

7. Growth & Development: increase in size/number of cells in organism

8. Nutrition: process of taking in/making organic nutrients and then breaking them down for energy

What is homeostasis?

maintaining stable internal conditions through a systems of both positive and negative feedback systems

What does “metabolism” mean?

refers to all the chemical reactions that occur in an organism

(1) Prokaryotic vs. (2) Eukaryotic

1. simple structure, no internal membranes, few organelles, and no nuclei

2. complex structure, many organelles, nucleus w/ DNA

What is the difference between (1) positive and (2) negative feedback?

1. enhances the stimuli or effects of until the event is over

2. reduces the original effect of stimuli until it reaches its ideal value or set point

What is the fight or flight response? What causes it and why is it important?

• innate and automatic response to when body is in immediate or prolonged situations/danger

• Caused by sympathetic nervous system who responds to stress

• We would die if we didn’t have one → helps us get out of immediate danger fast

Define hydrogen bonds

electrostatic attraction between polar molecules that occurs when a hydrogen atom bound to a highly electronegative atom experiences attraction to some other nearby polar molecule

Define cohesion

attraction between the same molecules due to hydrogen bonding

Define adhesion

attraction between 2 dissimilar surfaces/molecules to one another because of hydrogen bonding

Define monomer

single unit/building block of a biomolecule

Define polymer

many units/building blocks of a biomolecule

Define dehydration synthesis

reaction involving the removal of water into order to bond something

Define hydrolysis

reaction involving the addition of water in order to break a bond

What are the properties of water? Why are they important for living things?

• cohesion → high surface tension →

• cohesion → high heat of vaporization → temperature stabilizer through sweating (a lot of heat is absorbed from body before evaporating from skin)

• cohesion → high specific heat → acts as a temperature stabilizer (absorbs a lot of heat, but slowly)

• cohesion → less dense as a solid → during winter prevents further freezing of water sources

• adhesion & cohesion → capillary action → helpful in fluid transport in plants & animals

• adhesion → versatility as a solvent → allows for all our chemical rxns to occur because the necessity of an aqueous environment

• What are the elements in CARBS?

• What is its function?

• What is its monomer?

• What is its polymer?

• C, H, O

• Acts as (1) immediate energy w/ monosaccharides able to be delivered straight to cells directly for respirating out ATP (2) stored energy for later (3) structural support

  • Cellulose in plant cell walls/Chitin in fungi cell walls

• Monosaccharide (2:1 H to O ratio)

• Polysaccharide

• What are the elements in LIPIDS?

• What is its function?

• What is its monomer(s)?

• What is its polymer(s)?

• C, H, O

• Triglyceride → stored energy, heat insulation, padding

• Phospholipid → in all cell membranes to provide membrane structure

• Waxes → protective coating from water and from dehydration

• glycerol + 3 fatty acids

• Triglycerides, phospholipids, steriods

• What are the elements in PROTEINS?

• What is its function?

• What is its monomer?

• What is its polymer?

• C, H, O, N, maybe sometimes some S (whats up chons)

• Enzymes, contractile proteins, immune defense, transporting, structure, storage, hormones for signaling

• amino acids

• polypeptide

• What are the elements in NUCLEIC ACIDS?

• What is its function?

• What is its monomer?

• What is its polymer?

• C, H, O, N, P

• DNA that contains all genetic code for all inherited traits while RNA reads the genes, which is code, on DNA and synthesizes proteins

• Nucleotide

• Polynucleotide

General structure of carbs and its monomer

• 5-6 sided rings bonded by removal of water

General structure of lipids and its monomers

1 glyceride + 3 fatty acids branching off → triglyceride

General structure of proteins and its monomer

amino group on left and carboxyl group (-cooh) on right

top is R group bottom with have hydrogen

General structure of nucleic acids and its monomers

in rows of 2 nucleotides going down

monomer = 1 phosphate group, 1 5-carbon sugar either being ribose or deoxyribose, then a nitrogenous base

What is the relationship between nucleic acids and proteins?

DNA codes for proteins and in order to synthesize the protein, RNA will “read” DNA’s code (genetic information) and make it

What is transcription? Where does it occur in a cell?

• process where a segment of DNA is copied into messenger RNA (mRNA)

• occurs in the nucleus

Which molecules are involved in transcription?

DNA helicase

RNA polymerase

Free RNA nucleotides

mRNA

What are exons? What are introns? How is mRNA edited?

• coded regions that are spliced together

• uncoded regions that are cut out

• Final mRNA transcript will only consist of extrons

What is translation? Where does the process occur in a cell?

• process of “reading” the mRNA codons and putting together the correct sequence of amino acids

• in the cytoplasm and on a ribosome

How are mRNA, tRNA, involved in translation?

• mRNA carries the copied and coded genetic information to the cytoplasm and onto the ribosome

• tRNA will then use its anticodons to match up to the mRNA’s codons, bringing over a corresponding amino acid

What is a gene mutation?

a change in the order of nucleotides in the DNA

What is ATP? How is it used to do work in cells?

• Adenosine Triphosphate → unstable molecule with high energy

• When ATP hydrolyzes and breaks off a phosphate group, energy is released that can be used to do work in the cells

What is an enzyme? Why are they important in living things?

• a catalyst made up of special proteins that is required to start and speed up all chemical reactions in an organism by lowering activation energy

• it makes biochemical reactions happen faster when otherwise the reactions would just not occur or would occur at too slow of a rate to sustain life

How do enzymes work?

• Induced fit model → when substrate enters onto an enzyme’s active site, it will change shape and grip the substrate, bringing the substrate into a position that will enhance their ability to catalyze the reaction

  1. Substrate enters active site and enzyme grips (enzyme-substrate complex w/ highest energy)

  2. Enzyme’s active site lowers activation energy and speeds the reaction up

  3. Substrates are converted into products

  4. products are released

What factors affect the rate of enzyme action?

• Anything that causes a change in the active site shape (denaturing) by distributing interactions between amino acids

  • Temperature

  • pH levels

  • Salts

• Most enzymes function optimally at…

  • 37 ^oC (body temp)

  • ~7 but stomach enzymes ~2

  • ~1-2%

• Inhibitors

  • Competitive inhibition: inhibitor competes with substrate to the same active site to block it from entering so no more rxns continue

  • Noncompetitive inhibition: inhibitor attaches to an allosteric site of enzyme and changes the shape of the active site so substrate cant fit, so no rxns will continue

  • Feedback inhibition: the end product of a biochemical pathway will attach itself to an allosteric site of the first enzyme apart of the pathway to change the shape of its active site so the biochemical pathway will not continue when there is a sufficient amount of product, the rxn will resume when more end product is needed

• enzyme action will increase when the substrate amount increases until the rxn rate reaches the V_max (maximum rate of reaction) where all enzymes are in use so adding extra substrate would no longer increase the reaction rate since there is no enzyme to facilitate the reaction

what does it mean if a protein is denatured?

when a protein has changed shape and can no longer function

what causes proteins to denature?

• Temperature

• Changes in pH

• Salts