BIOCHEM 607 EXAM 1

Proteins that have crossed a membrane are no longer topologically inside the cell and must ___ to get back inside

____ move from compartment to compartment within a cell by ____ and _____

Many proteins have ____ at their amino terminus that direct ____ to cross the membrane.

T/F

Many proteins have internal signal sequences

Larger proteins pass through _____ by an ___ process

______ bind to _____ found on many nuclear bound proteins and facilitate transport into nucleus.

It generally requires multiple signals to transport proteins from the cytosol into the ___ of the _____

There are multiple _____ in the mitochondrial membrane and each interacts with a specific set of proteins

T/F Protein transport into mitochondria requires energy

Proteins enter ____ using a mechanism similar to mitochondrial entry

Proteins travel thru the ____ to many sites

Translocation across the ER membrane requires a ____ that binds to the _____ on the nascent peptide chain

The SRP signal sequence direct the ____ to the ER membrane

The coupling of ___ and____ allows transport across th ER membrane without andy additional energy

T/f
Most proteins are glycosylated in the mitochondria

Vesicles budding off the ____ are coated with molecules that direct them to specific locations in the cell

Integral membrane proteins that facilitate membrane fusion

proteins that facilitate docking of transport vesicles to specific locations

___ proteins are recruited into specific transport vesicles by ___ receptors

Different areas of the ___ (compartments) have different processing proteins

T/F

stacks within the golgi are connected

proteins destined for the _____ pass through the ____

Lysosomal proteins are glycosylated with ______-containing polysaccharide thats recognized by a ___ in golgi

2 pathways for transport of proteins through golgi to outside of cell?

____ secretory pathway results in a constant level of secretion of the protein

____ secretory pathway releases proteins to outside of cell in response to external stimuli

The ____ pathway to the outside of cell is the default pathway unless there are signals directing it to another pathway

Lipid synthesis occurs on the ____ side of the ____

T/F

There are fewmechanisms that transport newly made lipids to their final destinations

DNA and RNA are polymers of the monomeric unit ____

Each nucleotide is made of 3 components

DNA and RNA differ at __' carbon on the sugar how?

T/F
RNA cannot form double strands

Each double stranded DNA molecule has ___ potential open reading frames

____ can catalyze its own modification (splicing)

6 functions of RNA

2 processes that cells acquire nucleotides

____ synthesis of ____ results in synthesis of ____ that can be converted into ___ and ____

atoms in newly made purines come from:

___ and ___ regulate de novo synthesis of purines at multiple points in the pathway

Hypoxanthine guanine phosphoribosyl transferase (HGPRT) does what?

___ catalyzes ahydroxylase reaction leading to __ formation that can be exreted

Excess ___ is the cause of gout

Gout is most often caused by low ____ secretion but can also be caused by excess productions

Crystallization of _____ in the joints leads to a localized inflammatory response

____ is a ___ analog used to treat gout. It inhibits ____ thus preventing uric acid formation

HGPRT deficiency causes ____ that results in severe retardation, crippling gouty arthritis and self-mutilation

The breakdown of ___ can replenish the TCA cycle intermediates through ___ production

The atoms in the pyrimidine ring are derived from ____ and ____

The first 3 enzymes for ____ synthesis are located on the same protein (CAD protein)

dUMP is converted to TMP by ____, an enzyme requiring the transfer of a methyl group from____

Inhibitors of ____ are used as therapeutic agents for treating cancer and bacterial infections

____ substituted pyrimidine analogs that inhibit ____ are used as anticancer agents

____ converts ribonucleotides to deoxyribonucleotides at the ____ level (NDP to dNDPs)

Cellular signal transduction cassettes detect, amplify and integrate external signals made of ____ (3)

Cellular signal transduction cassetes use these steps:

____ are chem. messengers made by ___ cells that are secreted into blood and affect gene expression & protein synth

auocrine vs paracrine?

4 types of hormones?

3 cholesterol precursors for steroid hormones?

Steroid hormones
1-immediately diffuse out of __ into __
2-__ soluble
3-__ receptors are_target cell
4-__acting/__half-life than peptide hormones

Amine hormones
1)__ or __ derived
2)stored in __ until secreted
3)receptor has 2 locations:__

Polypeptide Hormones
1) __ enter blood
2) __ soluble
3)called __ and bind to __
4)intracell. affects mediated by __ that have __MW (examples __ or __)

G-Protein Coupled Receptors
1)__ proteins (extracell. __ terminus)
2)__transmembrne a-helices
3)_extra&intracell. loops 3rd_
4)__cellular C-terminus
5)no intrinsic __
6)G-protein activates __
-activates __ in __(signal cascade)
-__ inactivates __(kills cell response
-specificity by ___ that contains __ and __

Adenylyl cyclase activated by_

Each molecule of bound hormone can stimulate many __ that amplify original signal

2 bacterial toxins that target G-proteins by ADP ribosylating a-subunit of G-protein):

Ion-Channel receptors
-__ changes receptor shape and allows __ to flow thru channel

-__ affects ion-channels by preventing acetylch. release & cleaves proteins involving neurotransmitt docking vesicls.

Tyrosine kinase-linkd receptors
-no intrinsic __
-ligand binding forms __ that activates __ that __ downstream targets(signal cascade)

Intrinsic Enzyme Activity Receptors

-__-triggered protein kinases
-similar to __ b/c __
-__complex directly acts as__by __