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86 Cards in this Set

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Polypeptides are strings of amino acids that are assembled by what?

Ribosomes

tRNAs (with amino acids attached) used during translation are ___ (charged/uncharged)

Charged

What substances transport amino acids to the ribosome?

tRNAs

During translation, complementary base pairing takes place between the mRNA ___ (codon/anticodon) and the tRNA ___ (codon/anticodon)

mRNA codon, tRNA anticodon

One of the boundaries of translation is the start codon which corresponds to the ___ (N-/C-) or ___ (amino/carboxyl) terminus

N- or amino terminus

One of the boundaries of translation is the stop codon which corresponds to the ___ (N-/C-) or ___ (amino/carboxyl) terminus

C- or carboxyl terminus

What are the 2 ends of a polypeptide?

Amino and carboxyl

In translation, the 5' UTR and 3' UTR are segments of the mRNA ___ (outside/inside) the translated regions

Outside

The basic functions of ribosomes in eukaryotes and prokaryotes are ___ (the same/different)

The same

One function of ribosomes is to: Bind ___ (DNA/mRNA) and identify the ___ (start/stop) codon, which is where translation begins

Bind mRNA and identify the start codon

One function of ribosomes is to: ___ (Prohibit/Facilitate) complementary base pairing of mRNA codons and the corresponding tRNA anticodons

Facilitate

One function of ribosomes is to: Catalyze formation of ___ (hydrogen/phosphodiester/peptide) bonds between amino acids on the growing polypeptide chain

Peptide bonds

What 2 components make up ribosomes?

rRNAs and proteins

The ___ (A/P/E)-site of a ribosome binds a new tRNA molecule containing an amino acid to be added to the growing polypeptide chain

A-site

The ___ (A/P/E)-site of a ribosome holds the tRNA to which the polypeptide is attached

P-site

The ___ (A/P/E)-site of a ribosome provides an avenue for exit of the tRNA after its amino acid has been added to the chain

E-site

Between what 2 areas is the P-site located?

A-site and E-site

The first step in bacterial translation is the formation of what complex?

Pre-initiation complex

What 3 components make up the pre-initiation complex in bacterial translation?

Small ribosomal subunit, mRNA, and IF3

In bacterial translation, IF3 binds to the ribosome near the ___ (5'/3') end of the mRNA, and together with the ribosome, looks for a special sequence in the mRNA called the ___ (Shine-Dalgarno/TATA) sequence

5' end, Shine-Dalgarno sequence

The binding of the Shine-Dalgarno sequence with the 16S ___ (rRNA/tRNA) in the ribosome positions the start codon in the ___ (A/P/E)-site of the small subunit

rRNA, P-site

In bacterial translation, the first charged tRNA is a modified methionine called what?

fMet

In bacterial translation, after the pre-initiation complex is formed, what happens next?

The start codon is bound with its transfer RNA (fMet)

In bacterial translation, what compounds assist the fMet in binding to the start codon and prevent the large subunit from attaching?

Initiation factors

In bacterial translation, after the start codon is bound with its transfer RNA, what happens next?

The large subunit joins the small subunit to form the functional ribosome

In bacterial translation, after the functional ribosome is formed, the initiation factors ___ (stay/dissociate) and the ___ (A/P/E)-site is occupied by ___ (transcription factors/fMet)

initiation factors dissociate, P-site is occupied by fMet

In eukaryotic translation, the small ribosomal subunit complexes with what 2 components to form the pre-initiation complex?

Eukaryotic initiation factor (eIF) and a charged tRNAmet

In eukaryotic translation, the pre-initiation complex is recruited to the ___ (5'/3') cap region of the mRNA

5' cap region

In eukaryotic translation, the pre-initiation complex joins a group of at least four ___ (tRNA/eIF4) proteins that assembles at the 5' cap of the mRNA to form the initiation complex

eIF4 proteins

In eukaryotic translation, once the ___ (pre-initiation/initiation) complex is formed, it scans to move the small subunit along the ___ (5'/3') UTR in search of the ___ (start/stop) codon

Initiation complex, 5' UTR, start codon


In eukaryotic translation, the correct start codon can be located because it is embedded in a consensus sequence called what?

Kozak sequence

In eukaryotic translation, location of the start codon leads to recruitment of the large subunit using energy from what?

GTP hydrolysis

In eukaryotic translation, when then large subunit is added to the complex, what components dissociate?

eIFs

In translation, elongation begins with the recruitment of ___ (transcription/elongation) factor proteins that use energy of ___ (H2O/GTP) hydrolysis to recruited charged tRNAs to the ___ (A/P/E)-site

Elongation factor proteins, GTP hydrolysis, A-site

What enzyme catalyzes peptide bonds between amino acids at the P- and A- sites?

Peptidyl transferase

___ (Transcription/Elongation) actors help form peptide bonds using peptidyl transferase

Elongation

In translation, the first step in forming the peptide bond is breaking the bond between what 2 components?

fMet and its tRNA

___(Transcription/Elongation) factors translocate the ribosome

Elongation

Translocation of the ribosome moves the tRNA in the A-site into the ___ (P/E)-site and opens a new ___ (A/P/E)-site

P-site, A-site

In translation, bacteria and eukaryotes both use ___ (termination/release) factors to bind a ___ (start/stop) codon in the ___ (A/P/E)-site

Release factors, stop codon, A-site

Ribosomes account for what percentage of the mass of a bacterial cell?

25%

What is the name of structures the contain groups of ribosomes that all actively translate the same mRNA?

Polyribosomes

Each polypeptide-producing gene in eukaryotes produces ___ (monocistronic/polycistronic) mRNA

Monocistronic

___ (Monocistronic/Polycistronic) mRNA is an RNA molecule that directs synthesis of a single kind of polypeptide

Monocistronic

___ (Monocistronic/Polycistronic) mRNA is an RNA molecule that leads to the synthesis of several different proteins

Polycistronic

In bacteria, ___ (monocistronic/polycistronic) mRNAs are produced

Polycistronic

What is the name for the groups of bacterial genes that share a single promoter and produce polycistronic mRNA?

Operons

The genetic code contains ___ (more/less) codons than common amino acids, leading to ___ (conspiracy/redundancy)

More, redundancy

What two amino acids are the only amino acids not specified by at least two codons?

Methionine and tryptophan

All amino acids, besides 2, are specified by at least two codons called ___ (repetitive/synonymous) codons

Synonymous

tRNA molecules with different anticodons for the same amino acid are called what?

Iso-accepting tRNAs

What is the name for the relaxation of the strict complementary base-pairing rules at the third base of a codon?

Third-base wobble

Pairs of synonymous codons either both carry a ___ (purine/thymine) or both carry a ___ (adenine/pyrimidine)

Purine, pyrimidine

Most synonymous codons can be grouped into pairs that differ only in the ___ (1st/2nd/3rd) base

3rd base

Third-base wobble occurs through flexible pairing at the 3'-most nucleotide of the ___ (codon/anticodon) and the 5'-most nucleotide of the ___ (codon/anticodon)

3'-most nucleotide of the codon, 5'-most nucleotide of the anticodon

True or false: In third-base wobble, a pyrimidine must still-base pair with a purine

True

An overlapping genetic code ___ (is/is not) possible because the sequence of one codon would ___ (limit/free up) the possible sequences for the two ___ (subsequent/previous) codons

Is not possible, limit the possible sequences for the two subsequent codons

What is the name of the type of mutation that alters the reading frame of a sequence?

Frameshift mutations

With a frameshift mutation, all the codons ___ (before/after) the addition or deletion will specify the wrong amino acids

After

What is the term that refers to the specific codon sequence as determined by the start codon?

Reading frame

___ (Protein sorting/Post-translational polypeptide processing) modifies polypeptides into functional proteins by folding the polypeptide chains and by removal or chemical alteration of amino acids

Post-translational polypeptide processing

What type of enzymes carry out phosphorylation?

Protein kinases

What is the name of the most common amino acid modifications that can activate or inactivate a protein?

Phosphorylation

True or false: Some proteins only become functional once amino acids are removed or chemically altered after translation

True

What is the name of the proteins that assist in the folding of polypeptides, prevent unproductive folding, and undo incorrect folding?

Chaperones

___ (Protein sorting/Post-translational polypeptide processing) uses signal sequences/leader sequences to direct proteins to their cellular desinations

Protein sorting

What is the name of the sequences that protein sorting uses to direct proteins to their cellular destinations?

Signal or leader sequences

The signal sequence directs proteins to the ___ (endoplasmic reticulum/Golgi apparatus), where they are sorted for their specific destinations

Endoplasmic reticulum

Polypeptides destined for secretion are produced at the ___ (rough/smooth) ER

Rough

As translation begins, polypeptides with a signal sequence have their ___ (C/N) terminal pushed into the cisternal space of the rough ER thru receptors on the ER surface

N terminal

Once inside the rough ER, polypeptides have their ___ (coding/signal) sequence removed and are glycosylated and packaged into a ___ (larger protein/vesicle) for transport to the ___ (smooth ER/Golgi apparatus)

Signal sequence, vesicle, Golgi apparatus

In the Golgi apparatus, further ___ (polyadenylation/glycosylation) of proteins determines their ultimate locations

Glycosylation

Glycosylated proteins bind to different/specific receptors for packaging into ___ (ribosomal/transport) vesicles

Transport vesicles

Vesicles bud off of the Golgi apparatus ___ (cytoplasm/membrane) and transport proteins to their destinations

Membrane

Proteins that cannot fold properly are irreversibly bound to ___ (rough ER/chaperones) that are sequestered and ___ (maintained/destroyed)

Chaperones, destroyed

What type of diseases result when large amounts of mutant proteins accumulate without being destroyed?

Conformational diseases

What are 3 examples of conformational diseases?

Alzheimers, a form of Parkinsons, and Huntington disease

Attachment of an amino acid to tRNA occurs in the ___ (ribosomes/rough ER/cytoplasm)

Cytoplasm

Translation of cytoplasmic proteins occurs in the ___ (ribosomes/rough ER/cytoplasm)

Ribosomes

Translation of secreted proteins occurs in the ___ (ribosomes/rough ER/cytoplasm)

Rough ER

Are RNA primers used in protein synthesis?

No

What is the equation for finding the minimum size of a codon?

# of bases in DNA ^ minimum amount of bases per codon = amino acids

What enzyme can identify a mismatched nucleotide and remove it?

DNA polymerase

What enzyme catalyzes bond formation between nucleotide base pairs?

DNA polymerase

Topoisomerase breaks ___ (hydrogen/covalent) bonds in the DNA backbone

Covalent

SSBs prevent ___ (hydrogen/covalent) bonds between bases

Hydrogen