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bio 3
final exam new material
58
Biology
Undergraduate 2
12/28/2011

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Term
why is the cell membrane called a "mosaic"?
Definition
because of the different types of proteins insterspersed with the phospholipid bilayer
Term
what are two kinds of proteins in the cell membrane, and what's the difference between them?
Definition
peripheral proteins are attached to the cell membrane but don't penetrate. integral proteins penetrate the cell membrane.
Term
what limits the amount of glucose that gets into a cell?
Definition
how many transport proteins there are in the cell membrane
Term
how much energy do the transport proteins for glucose use?
Definition
none - it's a nonenergetic process
Term
why aren't O2 molecules stopped by the phospholipid bilayer?
Definition
most of the phospholipid bilayer consists of fatty acid chains, which are hydrophobic and will interact with  hydrophobic molecules. O2 is hydrophobic (nonpolar) and as such can get right through by diffusion.
Term
define: concentration gradient
Definition
the difference between the concentration of a molecule inside the cell and outside of it
Term
why can't glucose pass through the cell membrane by itself? (2)
Definition

1) it's too big

2) it's hydrophilic (from the hydroxyl groups) - it gets stopped by the fatty acid chains in the phospholipid bilayer.

Term
in a blood concentration reading, what ion would you expect to have a greater concentration inside the cell, and which a greater concentration outside the cell?
Definition
Na+ has a greater concentration outside, and K+ has a greater concentration inside.
Term
how could Na+ diffuse into the cell? why does it need this method?
Definition
it uses protein channels to diffuse in; it's hydrophilic (charged) and therefore can't get in by itself.
Term
what is the sodium-potassium ATPase pump?
Definition
a transport protein that pumps Na+ out of the cell when it tries to enter and K+ back in when it tries to get out
Term
why does the sodium-potassium ATPase pump need energy?
Definition
it opposes the natural force of diffusion
Term
where does the sodium-potassium ATPase pump get its energy from?
Definition
the breakdown of ATP into ADP (released energy from breaking one of the phosphate groups off)
Term
where does ATP store energy?
Definition
in the bonds between the three phosphate groups
Term
what is the second ability of ATPase?
Definition
other than being a sodium-potassium pump, it's the enzyme that breaks down ATP, supplying its own energy
Term
how does embryonic development provide an example of cell-cell recognition?
Definition
like cells match with like cells at the embryo develops
Term
what do membrane proteins have to do with cell-cell recognition?
Definition
the membrane proteins differ for different types of cells
Term
how does a hormone affect a cell?
Definition
it binds to its corresponding receptor protein
Term
define: ligand
Definition
general term for a molecule that binds to a protein receptor in the cell membrane
Term
what are the different types of cell membrane proteins? (5)
Definition

1) enzymes

2) transport proteins (facilitated diffusion)

3) protein channels

4) cell-cell recognition

5) receptor proteins

Term
define: nonpenetrating solute
Definition
a substance dissolved in a solution (like, say, sodium in water) that can't pass a membrane, while the water CAN
Term
define: tonicity
Definition
measure of the concentration of a nonpenetrating solute (like [Na+](aq))
Term
adding what to the blood will cause crenation?
Definition
Na+ -- the blood will become hypertonic, and water will drain from the cells to dilute it, causing them to shrivel
Term
what are two ways water gets through the phospholipid bilayer? which is the one most molecules use?
Definition
a small amount of water can get through the phospholipid bilayer on its own because it's such a small molecule. But most of it gets through via special protein channels called aquapores
Term
what can cause lysis?
Definition
drinking too much water -- will cause the inside of cells to be hypertonic relative to the outside, cause blood to flow in, and they explode
Term
what aspect of the cell increases when you decrease cell density? (for instance by adding new molecules)
Definition
fluidity
Term
why is the cell membrane's makeup called "fluid mosaic model"?
Definition
it's not a solid structure - it has a lot of parts, and they move around (mostly because of the fluid nature of the cholesterol molecules)
Term
what are contained within the cytoplasm?
Definition
organelles
Term
what sort of ribosome would produce insulin?
Definition
a bound ribosome (attached to the rough ER)
Term
where does protein synthesis/production occur?
Definition
ribosomes
Term
why would ovary cells have a lot of smooth ER?
Definition
ovaries produce a LOT of steroids (like hormones steroids) and so need a lot of smooth ER, which produce steroids
Term
what are the functions of smooth ER? (3)
Definition

1) steroid synthesis (also some other lipids)

2) detoxification

3) storage for calcium ions (in muscle)

Term
what two kinds of cells would be likely to have a lot of smooth ER, and why?
Definition

- liver, because smooth ER detoxes and that's where most detoxification happens in the body

- ovary cells, because they produce a lot of hormones, which are steroids; and steroids are produced in the smooth ER

Term
what is the function of rough ER?
Definition
it modifies the proteins that the ribosomes produce
Term
what are the two most common things the rough ER does to a protein?
Definition

1) adds a carbohydrate molecule (making it a glycoprotein)

2) package the protein into a vesicle (a little membrane-bound sac)

Term
where do proteins contained in vesicles go after being released from the rough ER?
Definition
the golgi complex - go in the convex end, are modified (cutting a little bit off), packaged in a secretory vessel, which fuses into the cell membrane and undergoes exocytosis
Term
what is exocytosis?
Definition
the secretory vessel fuses to the cell membrane and integrates into it, allowing the packaged protein to be secreted outside the cell and adding to the cell membrane structure
Term
what is a hydrolitic enzyme and where are they contained?
Definition
a very powerful enzyme that breaks things down - contained inside the lysosomes
Term
what is the pH of a lysosome like?
Definition
acidic - around 5 or so. the outside cytoplasm is basic. the reason lysosomes have to be acidic is because the hydrolitic enzymes are active in acidic environments
Term
what are the functions of the lysosomes? (3)
Definition

1) phagocytosis

2) programmed cell death

3) lipid macromolecule breakdown

Term
what is phagocytosis?
Definition
when a white blood cell (neutrophil) meets a bacterial cell it envelops it and internalizes it into its cell structure - enters the cytoplasm. Then the bacterial cell is broken down by the lysosomes. 
Term
what causes taysachs disease?
Definition
there aren't enough enzymes in the lysosomes, so the lipids in the neurons of the brain don't undergo programmed cell death, so there is an overload
Term
why do mitochondria have christae?
Definition
to increase the membrane area
Term
what are the components of chromosomes?
Definition
mostly DNA, some proteins.
Term
where are ribosomes assembled?
Definition
in the nucleolus
Term
what is rRNA?
Definition
ribosomal RNA - makes up ribosomes
Term
what is the nuclear envelope composed of?
Definition
TWO phospholipid bilayers (double membrane)
Term
how to ribosomes get past the nuclear envelope?
Definition
travel through nuclear pores
Term
what are the three structures that make up the cytoskeleton? (smallest to largest)
Definition

microfilaments

intermediate filaments

microtubules

Term

match the protein to the structure:

 

microfilaments, intermediate filaments, microtubules

keratin, tubulin, actin

Definition

microfilaments: actin

intermediate filaments: keratin

microtubules: tubulin

Term
what are the two basic functions of the cytoskeleton?
Definition

- support

- mobility

Term
where are three places microtubules provite motility, and what form do they take?
Definition
cilia in the throat and the fallopian tubes transport mucuous and eggs, respectively; and flagella in sperm.
Term
what is coupling (in a chemical reaction context)?
Definition
exergonic reactions produce energy that endergonic reations need - like redox reactions
Term
what are three things that are produced during glycolysis?
Definition

1) 2ATP

2) 2 pyruvate

3) NADH

Term
what is the feeder molecule that starts off the krebs cycle? the electron transport chain?
Definition

krebs cycle: pyruvate

electron transport chain: NADH

Term
what is a very common componant of the molecules in the electron transport chain?
Definition
Fe (iron)
Term
what are two common locations for Fe in the body?
Definition

- hemoglobin

- the molecules of the electron transport chain

Term
what is the final electron receptor in the electron transport chain?
Definition
oxygen
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