Midterm Exam 1

Question 1

What are the 3 main tenets of cell theory?

Answer 1

1. All living things are made from cells
2. Cells are the smallest forms of life
3. Cells form from existing cells through division

Question 2

Scientific Method Steps

Answer 2

1. Identify problem/gap in knowledge
2. Develop hypothesis
3. Experimentation
4. Data analysis
5. Reject or support hypothesis

Question 3

Primary Protein Structure

Answer 3

Linear amino acid sequence

Question 4

Secondary Protein Structure

Answer 4

Either spiral (alpha-helix) or sheet (beta-pileated sheet)

Question 5

Tertiary Protein Structure

Answer 5

3D folding

Question 6

Quaternary

Answer 6

Two or more polypeptide chains bind together

Question 7

Dideoxy DNA Sequencing

Answer 7

Uses ddNTPs to pause transcription at each nucleotide, allowing for a list of target nucleotides

Question 8

3 Approaches to identify a drug altering protein function

Answer 8

1. Drug may inhibit homologous proteins to target one
2. Use computer model to determine potential binding sites
3. “Grocery store approach”

Question 9

Light vs. electron microscopy

Answer 9

Light microscopy observes from 500nm to 5mm

Electron microscopy observes from 1nm to 100microm

Question 10

Western Blotting

Answer 10

A large group of proteins is separated by electric current through gel, wells are probed with antibodies which will darken on nylon sheet when contacting the target well

Question 11

What does the sgRNA in CRISPR Cas technology bind to?

Answer 11

The Cas9 protein and the target gene

Question 12

Resolution

Answer 12

The ability to discern two nearby objects as being distinct

Question 13

Contrast

Answer 13

How different one structure looks from another

Question 14

Flagella microtubules vs. motor proteins

Answer 14

Microtubules are fixed in place, whereas the motor proteins are free to move along them

Question 15

What is needed to move a lipid from one membrane leaflet to the other?

Answer 15

ATP and Flippase

Question 16

Two main purposes of catabolic reactions

Answer 16

1. Recycling organic monomers
2. Synthesis of energy intermediates (ATP)

Question 17

3 types of membrane proteins

Answer 17

Transmembrane
Lipid-Anchored
Peripheral membrane

Question 18

ATP hydrolysis ____s with an endergonic reaction

Answer 18

Couples

Question 19

Enzyme-catalyzed reactions steps

Answer 19

1. Protein binds to substrate
2. Induced fit occurs
3. Products form
4. Products are released

Question 20

How do enzymes decrease energy of activation (Ea) for reactions?

Answer 20

Strain bonds, move reactants closer together, and change local environment (pH)

Question 21

Do enzymes effect direction of reactions

Answer 21

NO!

Question 22

How does sucrose enter a cell?

Answer 22

First, ATP is hydrolyzed as an H+ pump moves ions out of cell against the gradient via primary active transport.

Next, an H+/sucrose symporter moves both H+ ions and sucrose into the cell down the gradient through secondary active transport.

Question 23

Proteins are sorted to their correct destination through

Answer 23

Remaining in the cytosol, co-translational sorting (ER), or post-translational sorting (nucleus, peroxisome, mitochondria)

Question 24

Vesicular transport model vs. cisternal maturation model

Answer 24

Vesicles bud from ER, go to cis-med-trans Golgi (Golgi stays intact).

Vesicles from the ER fuse to form new cis Golgi, moving med to trans, losing trans compartment.

Question 25

Fluid Mosaic Model

Answer 25

Lipids, proteins, and carbohydrates can move freely in the membrane relative to each other

Question 26

Transport Proteins

Answer 26

Conformationally changes to switch access of solute from one side of membrane to the other (uniporter, symporter, antiporter)

Question 27

Competitive vs. Noncompetitive enzyme inhibition

Answer 27

Competitive inhibition binds to the active site of the substrate, effectively disabling the enzyme, increasing Km value.

Noncompetitive inhibition binds to the allosteric site, limiting function and decreasing Vmax value.

Question 28

Some enzymes require ____

Answer 28

Prosthetic groups (permanently attached), cofactors (temporarily attached), and coenzymes (organic molecule participating in the reaction but unchanged)

Question 29

Cells make ATP by

Answer 29

1. Substrate-level phosphorylation, where enzyme transfers phosphate from organic molecule to ADP
2. Chemiosmosis, energy of electrochemical gradient used to make ATP

Question 30

Regulation of metabolic pathways

Answer 30

Occurs through gene regulation, cell regulation, and biochemical regulation

Question 31

Proteasomes

Answer 31

Large complexes that break down misfolded proteins tagged with ubiquitin, and using protease enzyme, cleaves into amino acid to be recycled

Question 32

Autophagy

Answer 32

A worn-out organelle is enclosed by a membrane tubule which fuses to a lysosome and recycles the basic organelle components

Question 33

Pulse-Chase Assay

Answer 33

Radioactive amino acid injection quickly followed by a non-tagged amino acid injection. Samples of pancreatic cells taken periodically, stained, and observed under a transmission electron microscope (TEM)

Question 34

Passive Transport

Answer 34

Moving of molecules down a gradient, either with a channel protein (facilitated diffusion) or without (simple diffusion)

Question 35

Endocytosis

Answer 35

Moves material into cell via receptor-mediated processes, pinocytosis (cytosol liquids), and phagocytosis (large molecules like bacteria)

Question 36

Ribozymes

Answer 36

RNA catalysts used in important cell reactions (Altman’s discovery)