Biology EK 1001

Question 1

In periods of low water intake, renin angiotensin feedback mechanism is used to minimize the amount of water lost by the system. The kidney works in conjunction with which of the folowing organs to excrete acidic metabolites and regulate acid-base buffer stores?

Answer 1

Lungs

Question 2

Which organs can use ketone bodies as a energy source? Which can’t?

Answer 2

Ketone: Brain, Heart, Muscle

Liver can’t use ketone bodies

Question 3

Albumin makes up 55% of plasma proteins. Fatty acids bind albumin for what reason?

Answer 3

Non-covalent binding with albumin increases over-all lipid solubility.
Albumin increases vascular osmolarity
If no albumin, increase in edema

Question 4

The crystal structure of a mutant mitochondrial enzyme aconitase has been determined. What can directly affect aconitase enzyme activity?

Answer 4

pH, temperature, Substrate Concentration

Question 5

Lipids are less dense than protein, the lower the density of a lipoprotein the less protein it carries. Which of the following molecules has the highest lipid density.

Answer 5

Chylomicron

Question 6

Shape is important for binding of the relevant peptide to the receptor protein on the cell surface. Which of the following amino acids should be used to bind to a sterically hindered receptor site?

Answer 6

Glycine, question is looking for smallest Amino Acid

Question 7

During carbohydrate metabolism, NADH is produced in which of the following locations?

Answer 7

Cytosol: Glycolysis

Mitochondrial Matrix: Krebs Cycle 3NADH

Question 8

When you lower Activation Energy

Answer 8

Increase forward and backwards reaction, but not equally(?)

Question 9

Enterokinase is composed of 80000 residues and is derived from a single chain precursor. Disulfide bond disruption and liquid chromatography reveal two different effusion rates. Explain, what could be true.

Answer 9

Two different effusion rates means there are two strands with different weights.

Question 10

In order to maximize ATP production, what can serve as initial reactant for glycolysis

Answer 10

Glucose, Hexose sugars.

Fructose and Galactose can be converted to hexose, and can enter glycolysis as Fructose 6 Phosphate and Galactose 6 Phosphate (but won’t be considered a reactant)

Question 11

Citric Acid Cycle products

Answer 11

3 NADH
1FADH2
Oxaloacetate (regenerated)
GTP

Question 12

Helicase is the enzyme that “unzips” the helix. In order to maintain the “unzipping”, SSBP is expected attach to which nucleotide element

Answer 12

ssDNA

Question 13

How man chromosomes are present in a human somatic cell after the S phase?

Answer 13

46 chromosomes

Question 14

Polycistronic mRNA

Answer 14

in prokaryotes, genes of similar function are often arranged adjacent to each other on the chromosome and are transcribed as a single polycistronic mRNA

Question 15

Southern blot

Answer 15

gel electrophoresis to detect DNA

Question 16

Western blot

Answer 16

gel electrophoresis to detect Protein

Question 17

Northern blot

Answer 17

gel electrophoresis to detect RNA

Question 18

Where do viruses acquire envelope (glycoprotein covered)

Answer 18

Most viruses acquire from plasma membrane

If viral assembly occurs in the nucleus, virus acquires envelope from nuclear membrane

Question 19

DiGeorge’s syndrome presents as a severe T-cell deficiency. Which of the following organs failed to develop in an individual diagnoses with DGS?

Answer 19

Thymus

Question 20

Which location has the greatest surfactant production?

Answer 20

Lung

reduces interfacial surface tension between liquids–present in alveoli

Question 21

Possible movement type associated with proteins in the plasma membrane

Answer 21

Motion along the plane

Sinking in and out

Question 22

The nucleocapsid, an outer portion of the naked capsid virion, protects the virion from the conditions in the gastrointestinal tract. What is a likely mode of transmission for the naked capsid virion?

Answer 22

Naked capsid virus is protected by nucleocapsid from drying, acids and bile, making it resistant to GI tract conditions. It can be assumed that the virus infect the GI through fecal-oral route.

Question 23

Blood plasma

Answer 23

blood and everything EXCEPT red blood cells

amino acids, albumin, glucose, Na, Ca, Cl, HCO, are all present

Question 24

Mitochondria

Answer 24

Inter-cristal space (Matrix) houses low H+ concentration.
H+ pumped out of the matrix into the intermembrane space by the electron transport chain.
Intermembrane space has high H+ concentration

Question 25

Endocytosis

Answer 25

Membrane bound vesicle will be digested by primary lysosomes
Requires ATP
Depends on the presence of a cell surface receptor to initiate recognition sequence

Question 26

Thermogenin is a specialized inner membrane protein found in mitochondria. It transports protons back into the matrix bypassing the ATP synthase. What is expected result post-thermogenin administration?

Answer 26

Elevated blood temperature, because electron transport chain produces 2 forms of energy–Energy and ATP. When there is no ATP, heat increases

Question 27

Microtubules

Answer 27

serve ascytoskeletal structural components
responsible for chromosome segregation during cell division
intracellular transport and organelle positioning
guide cellular movement via cilia flagella

Question 28

Actin

Answer 28

Thin microfilament, muscle

Question 29

Inhibit TCA

Answer 29

inhibits the electron transport chain
pyruvate made from glycolysis, which would have gone through TCA cycle, goes through fermentation to produce lactic acid or ethanol (yeast). Because no TCA cycle, no NADH and FADH2 for ETC, so ETC stops

Question 30

Gluconeogenesis

Answer 30

Occurs in Mitochondria and Cytosol

Question 31

Viral Infection specificity

Answer 31

Must overcome

• physical barrier, local temperature, pH, non-specific body secretions
• host cell must be able to support viral replication with ATP and enzymes

Question 32

Peripheral Proteins

Answer 32

Usually surface receptors (NEVER CHANNELS)

Question 33

Gluconeogenesis

Answer 33

Maintain constant blood glucose levels
Precursor must contain 3 carbons in backbone. Free fatty acids are broken down to acetyl coA, which is a 2 carbon molecule that cannot enter gluconeogenesis

Question 34

Prosthetic Group

Answer 34

Attach to enzymes via covalent bonds

Question 35

Hemoglobin

Answer 35

Higher O2 affinity than adult hemoglobin since it has to steal O2 from maternal blood.
CO binds tightly, preventing oxygen from binding
Hemoglobin displays positive cooperative oxygen binding