Cell and Molecular Biology - Exam 1 Master Set

What are the 4 major classes of cell biomolecules?

Lipids, proteins, carbohydrates, nucleic acids

Lipids contain fatty acids for ___ and phospholipids for ____

energy storage, cell membranes

Proteins are linear polymers of:

amino acids

Carbohydrates have the purpose of ____ and are made up of ____

energy storage, monosaccharides

Nucleic Acids are polymers of ____

nucleotides

The four bases in order A, C, G, and T/U are

Adenine, Cytosine, Guanine, Thymine/Uracil

Which DNA base pairs bond to each other?

A:T, G:C

The Central Dogma is

the method of transcription and translation in the cell

Codons are ___ and their purpose is to _____

Nucleotide triplets, encode amino acids

Degenerate code is the idea that

most amino acids are encoded by >1 codon

Chromosomes are

tightly wound DNA in the nucleus

The genome is

All of our chromosomes together

The Plasma membrane is made of a:

Lipid bilayer

“Fluid Mosaic” refers to

embedded proteins that are part of the cell membrane

Cytoplasm is the

cytosol and organelles

The nucleolus is in the ____

Nucleus

The membrane of the nucleus is called the ____ and it has ____ layers of membrane and ____

nuclear envelope, two, nuclear pores

Smooth ER is responsible for

lipid synthesis, Ca2+ ion storage, detoxification

The Rough ER is responsible for ___ and is studded with ____

protein synthesis, ribosomes

Ribosomes have ___ subunits, and are both ___ and ____

two, free, bound

The Golgi Apparatus is responsible for

modifying and sorting products from the ER

Vesicles are part of the ____ pathway

Secretory

Lysosomes are responsible for ____ material in and outside the cell, and do so with this enzyme they contain: ____

degrading, acid hydrolases

Mitochondria produce ____ and are made up of _____ (the folded bits) and a _____ (filling)

ATP, cristae, matrix

The cytosol is ____ portion of the cell enclosed by the plasma membrane

soluble

Lenth scale review: rank the cell parts in order of size (Biggest>smallest, 9 total)

Mammalian cell > nucleus> mitochondria > lysosomes > Er = Golgi > ribosome = cytoskeleton > protein

Amino acids are composed of a _____ group (-NH2), a _____ group (-COOH), and a ____ group (R)

amine, carboxylic acid, side

Amines are _____ (pka > ___) and carboxylic acid is ____ (pka < ___)

basic, 9, acidic, 3

Amino acids are strung together via ___ bonds and chains are read from the ___ terminus to the ____ terminus

amide, N, C

D and E side groups are ____ charged, so they are _____

negatively, acidic

R, K, and H are ____ charged, so they are _____

positively, basic

N, Q, S, T, Y are ___ charged, so they are ____

not, polar

S, T, Y, and H are ____

phosphorylatable

F, Y, and W are ____ side chains (absorb UV)

aromatic

V, L, and I are ____

aliphatic

“Benign” side chains

G, A

“metabolic intermediates” side chains

N, Q

Sulfur-containing side chains

C, M

“Kink-inducing” side chains

P

A disulfide bond is an S-S bond between two ____, and it forms readily in _____ environments

cysteines, oxidizing

The primary protein structure is the

order of side chains from N-C terminus

The secondary protein structure is caused when the primary structure folds, driven by _____. The two structures that make up the secondary structure are ____

H-bonds, alpha helix and beta sheet

The formation of the tertiary structure is driven by ______

hydrophobic interactions

What is the Quaternary structure?

association of multiple polypeptides into a larger complex

What is the predecessor to GLP-1?

Proglucagon

Which enzyme is responsible for converting proglucagon into GLP-1?

Protease

What is the specific function of proteases?

cleave peptide bonds

What is the specific function of protein kinases?

Add a phosphate group to S/T/Y residues

What class of peptide is GLP-1?

hormone

What is the name of the cell signaling system in which signaling molecules are carried through the bloodstream to target cells?

endocrine

What is the name of the receptor that GLP-1 binds to, and what type of receptor is it?

GLP-1R, GPCR

GPCRs contain an _____ domain (outside the cell), and a _____ domain (inside the cell) which is paired with the ______

extracellular, cytoplasmic, G protein

G proteins are inactive when ____ is bound to them, and active when _____ is bound to them

GDP, GTP

The G proteins that are found on GPCRs are what kind of G protein?

heterotrimeric

What are the three subunits of heterotrimeric G proteins?

Alpha, beta, gamma

Which heterotrimeric G protein subunit dissociates when the ligand binds to the extracellular side of the GPCR?

alpha unit

When a ligand binds to a GPCR, the alpha subunit gets activated by switching GDP for

GTP

G_{alpha s} is ____ and G_{alpha i} is _____

stimulatory, inhibitory

Adenylate cyclase is activated when the _______ of a GPCR dissociates and binds to it

alpha subunit

When active, Adenylate Cyclase converts ___ into _____

ATP, cAMP

cAMP is broken down by

phosphodiesterase

cAMP activates what molecule?

PKA

Enzymes act on ____ to yield ____

substrates, products

If a molecule can “tell the difference between isomers”, it is

stereo-specific

Different enzymes that catalyze the same chemical reaction are called

isozymes

Peptidases are responsible for what enzyme function? (In addition to proteases)

hydrolytic cleavage of peptide bonds

Phospholipases are responsible for which enzyme function?

cleave phospholipids

Synthases are rsponsible for which enzyme function?

synthesis of biomolecules

The site that the the substrate binds to on an enzyme is called the _____/_____ site

catalytic/active

“Induced fit” refers to

The ability of an enzyme’s active site to mold to fit when binding its specific substrate

Enzymes ____ activation energy to quicken the rate of reaction

lower

Temperature and pH can potentially _____ an enzyme, reducing its function

denature

Cofactors are molecules that are necessary in some cases to ____. An example of them are ____

keep enzymes activated, metal ions

______ participate directly in enzymatic function to transfer things (like electrons, amine groups, etc.)

coenzymes

What is the term for the rate at saturation for 1 enzyme molecule?

turnover rate

What is the toxin that causes Botulism

botulinum toxin

____ inhibitors compete with the substrate to bind to the active site of the enzyme

competitive

Competitive inhibitors alter ____ but not ____ (in relation to the Michaelis-Mentin equation)

Km, Vmax

________ inhibitors bind to the ______ site of an enzyme, somewhere besides the active site

noncompetitive, allosteric

Phosphatase protein does what?

remove phosphate group

Regulation by _____ means that the enzyme needs to be in a place where it will “find” the substrate, therefore it has to be proximal to it

localization

Regulation by _________ means that the kinase relies on these to be activated/deactivated

binding partners

the “Hill Coeffcient” n indicates the degree of ______ of a molecule (the higher the n, the more of this it is)

cooperativity

_____ are structurally and functionally distinct regions of a single protein

Domains

______ are separate proteins that are stuck together to form the enzyme (each protein in the assembly is one of these)

Subunits

Membrane proteins called ______ bind to one another to pull vesicles into the cell by connecting the vesicle membrane to the cell membrane

SNARE

______ extends from the vesicle membrane and _____ extends from the cell membrane during vesicular fusion

vSNARE, tSNARE

______ is a type of vSNARE found in synaptic vesicles containing neurotransmitters

Synaptobrevin

Antitoxins ____ (disable) toxins that have not yet entered nerve cells

neutralize

C botlulinim multiplies in the gut and secretes a toxin that is transported across the ________ and then circulates in the blood stream. It then binds to the membranes of ______

intestinal epithelium, motorneurons

______ is the process by which a cell internalizes (pulls in) a compound after it binds to a membrane protein

endocytosis

Once the botulinum toxin is released into a neuron, the _______ of the toxin separates itself, because its only purpose is to help the toxin penetrate the membrane into the cell. This is also known as a _______ because it cleaves synaptobrevin

light chain, zinc endopeptidase

_____ are linear polymers of _____ (What DNA and RNA are)

nucleic acids, nucleotides

The ______ is the _____ without the phosphate group (in relation to nucleic acids)

nucleotide, nucleoside

Nucleotides are linked by ______ bonds

phosphodiester

The _____ is on the 5' carbon of the sugar, and the _____ is on the 3’ carbon of the sugar

phosphate, hydroxyl group

DNA length is measured by the number of _______; the two strands of DNA run ______ to each other

base pairs, antiparallel

DNA has a unique property to _____ when heated and then _____ when cooled back to room temperature

denature, anneal

A chromosome is a

DNA strand and all its genetic information

Humans have ____ pairs of chromosomes, making ____ total

23, 46