MCAT BIO Cell Biology

Question 1

Chromosomes have a ___ near the middle to ensure that newly replicated chromosomes are sorted properly during cell divison, one copy to each daughter cell

Answer 1

Centromere

Question 2

__is a region in the nucleus that functions as a ribosome factory.

Answer 2

Nucleolus

Question 3

___ consists of loops of DNA, RNA polymerases, rRNA, and the protein components of the ribosome

Answer 3

Nucleolus

Question 4

What role do the loops of DNA in the nucleolus play?

Answer 4

They serve as template for ribosomal RNA production

Question 5

The nucleolus is the site of transcription of rRNA by___

Answer 5

RNA polymerase 1

Question 6

The membrane of the endoplasmic reticulum is at points continuous with the ____

Answer 6

outer nuclear membrane of the nuclear envelope

Question 7

The lumen of the ER is continuous with the __

Answer 7

space between the two nuclear membranes of the nuclear envelope

Question 8

Where is pyruvate dehydrogenase and the enzymes of the Krebs cycle located?

Answer 8

In the interior of the mitochondria, the MATRIX

Question 9

__ is the site of the proton gradient used to drive ATP synthesis by ATP synthase

Answer 9

Inner membrane Matrix of mitochondria

Question 10

The ___of the mitochondria is impermeable to the free diffusion of polar substances, like protons

Answer 10

Inner membrane of Matrix of mitochondria

Question 11

The ___ of the mitochondria is smooth and contains large pores that allow free passage of small molecules

Answer 11

outer membrane of the mitochondrial matrix

Question 12

Why is the inner membrane (matrix) folded into cristae?

Answer 12

To increase surface area and allow for increased electron transport and ATP synthesis per mitochondrion

Question 13

Where are the enzymes of glycolysis located?

Answer 13

Cytoplasm

Question 14

Mitochondrion and ____look pretty familiar

Answer 14

Gram-negative bacterium

Question 15

What difficulty may be encountered in translation of a mitochondrial gene moved to the nucleus?

Answer 15

Coding system of cellular genome is different from that of mitochondrial genome

Question 16

___is a large system of folded membrane accounting for over half of the membrane of some cells

Answer 16

Endoplasmic Reticulum (ER)

Question 17

__ contains enzymes involved in steroid hormone biosynthesis or degradation of environmental toxins

Answer 17

Smooth ER

Question 18

Proteins translated on____ are headed toward peroxisomes, mitochondria, nucleus, or inside cell

Answer 18

Free cytoplasmic ribosomes

Question 19

Proteins synthesized on the rough ER will end up ___, ___,___

Answer 19

1. secreted into the extracellular environment
2. Integral plasma membrane proteins
3. Membrane or interior of ER, Golgi apparatus, lysosomes

Question 20

Integral membrane proteins have sections of hydrophobic amino acid residues called __that pass through the lipid bilayer membranes

Answer 20

Transmembrane domains

Question 21

What are the 3 functions of the Golgi apparatus?

Answer 21

1. modification of proteins made in the RER
2. Sorting and sending proteins to correct destinations
3. Synthesize macromolecules like polysaccharides to be secreted

Question 22

Vesicles from the ER fuse with the ___ of the Golgi apparatus

Answer 22

Cis track nearest to the rough ER

Question 23

Proteins leave the Golgi apparatus from the ___

Answer 23

Trans stack farthest from the Rough ER

Question 24

___is a membrane-bound organelle that is responsible for the degradation of biological macromolecules by HYDROLYSIS

Answer 24

Lysosomes

Question 25

Process of degradation of organelles by lysosomes

Answer 25

Autophagy

Question 26

Macriphages of the immune system engulf bacteria and viruses the particles end up in a phagocytic vesicle which will fuse with the __

Answer 26

lysosome

Question 27

___refers to lysosomal digestion of unneeded secretory products

Answer 27

Crinophagy

Question 28

Enzyme responsible for degradation in lysosomes is __

Answer 28

acid hydrolases

Question 29

The pH of lysosome is around __ making its enzyme acid hydrolase active

Answer 29

5

Question 30

What are functions of peroxisomes?

Answer 30

1. Breakdwon peroxide by use of enzyme catalase 2. lipid breakdown in many cells 3. Asssiste in detox of drugs and chemicals in liver cells

Question 31

___ is the enzyme in peroxisomes that breaks down peroxide into H20 and O2

Answer 31

Catalase

Question 32

Integral membrane proteins are held in the membrane by __

Answer 32

hydrophobic interactions

Question 33

What holds peripheral membrane proteins to integral proteins ( 2 things)

Answer 33

Hydrogen bonding | Electrostatic interactions

Question 34

What interaction between fatty acid side chains are a major determinant of membrane fluidity?

Answer 34

van derr Waals interactions

Question 35

Increasing the unsaturated fatty acid content of the membrane will ____

Answer 35

Increase fluidity since they have fewer van derr waals interactions

Question 36

Why is molality better to use when measuring properties involving temperature?

Answer 36

Molality does not change with temeprature

Question 37

___ tells us how many ions one unit of a substance will produce in a solution

Answer 37

van't Hoff (ionizability) factor (i)

Question 38

__ depend on the number of solute particles in the solution rather than the type of particle

Answer 38

Colligative properties

Question 39

What are the four major colligative properties tested on the MCAT?

Answer 39

vapor-pressure depression boiling-point elevation freezing-point depression osmotic pressure

Question 40

__ is the pressure exerted by the gaseous phase of a liquid that evaporated from the exposed surface of a liquid

Answer 40

Vapor pressure

Question 41

___ is the movement of a molecule down a gradient with the help of a protein

Answer 41

Facilitated diffusion

Question 42

The ____ established by the Na+/K+ ATPase is the driving force behind secondary active transport of many different molecules, including sugars, and amino acids

Answer 42

concentration gradient of HIGH SODIUM OUTSIDE OF THE CELL

Question 43

What are thee ways the activity of Na+/K+ ATPase is important?

Answer 43

1. To maintain osmotic balance between the cellular interior and exterior 2. To establish the resting membrane potential 3. To provide the sodium concentration gradient used to drive secondary active transport

Question 44

___ is a second messenger of the hormones epinephrine and glucagon, chich cause energy mobilization (glycogen and fat breakdown)

Answer 44

cyclic AMP (cAMP)

Question 45

A___ does not directly transduce its signal but transmits it into the cell with the aide of a second messenger, the most important second messenger being (cAMP)

Answer 45

G-protein linked receptor

Question 46

The common theme of all G-protein based signal transduction is ___

Answer 46

their reliance on a G-protein, which is a signaling molecule that binds GTP

Question 47

The animal ____ provides the structural support supplied by the cell wall in bacteria, plants and fungi

Answer 47

Cytoskeleton

Question 48

What three proteins compose the animal cytoskeleton?

Answer 48

microtubules intermediate filaments microfilaments

Question 49

___is a hollow rod composed of two globular proteins a-tubulin and B-tubulin, polymerized noncovalently

Answer 49

Microtubule

Question 50

___ radiate out from the centrioles during mitosis

Answer 50

Microtubules

Question 51

Microtubules radiating out from the centrioles during mitosis are called __ because they are star shaped

Answer 51

Aster

Question 52

Epithelial cells in the skin are held together tightly but do not form a complete seal; this is accomplished by __

Answer 52

desmosomes

Question 53

Heart muscle cells are connected by holes called __ that allow ions to flow back and forth between them

Answer 53

Gap junctions

Question 54

___ also termed occluding junctions because they dont just join cells but form a seal between the membranes of adjacent cells

Answer 54

Tight junctions

Question 55

___ form pore-like connections between adjacent cells, allowing the two cells' cytoplasms to mix

Answer 55

Gap junctions

Question 56

___ in smooth muscle and cardiac muscle allow the membrane depolarization of an action potential to pass directly from one cell to another

Answer 56

Gap junctions

Question 57

__ phase includes mitosis and cytokinesis

Answer 57

M phase