Why is the addition of the 5' cap structure critical?

an mRNA to be translated in the cytoplasm, is needed to protect the growing RNA chain from degradation in the nucleus by 5' exonucleases, the cap also helps the transcript bind to the ribosome during the protein synthesis

(True or False) RNA polymerase III synthesizes rRNAs involved in facilitating protein synthesis by the ribosome

False

Which of the following is an mRNA processing reaction?

Removal of introns from the heterogenous nuclear RNA

Which of the following sites on a gene is important for recognition of the beginning the ends of intron sequences?

splice sites GU and AG

Splicing of a newly synthesized RNA molecule to remove introns and join exons

Occurs in the nucleus and involves a complex of small nuclear RNA and protein molecules

What will be the sequence of the single-stranded RNA transcribed from the following segment of double-stranded DNA?

5'-TTGCACCTA-3'

3'-AACGTGGAT-5'

5'-UUGCACCUA-3'

Telomeres-

consist of repetitive DNA sequences found at the ends of chromosomes.

The nucleotide is composed of

a pentose sugar, a phosphate, and a base (G, C, A, T)

How many hydrogen bonds bind G and C and how many bind A and T?

3 hydrogen bonds bind G and C and 2 hydrogen bonds bind A and T

DNA is composed of the following bases-

adenine (A), guanine (G), cytosine (C), thymidine (T)

The nucleotides in each strand are linked by-

strong (covalent) chemical bonds

The nucleosome consists of

a complex of 8 histone proteins ( 2 molecules of each histone H2A, H2B, H3, and H4) with double-stranded DNA wound around it

Which of the following statements about histone proteins is correct?

Nuclear DNA associates with histone proteins to form chromatin

The phosphodiester bonds are bonds that form between

3'-OH groups of the deoxyribose sugar on one nucleotide with the 5' phosphate groups on the adjacent nucelotide

Chromatin consists of-

very long double-stranded DNA molecules, nearly an equal mass of rather small basic proteins termed histones, as well; as smaller amounts of nonhistone proteins and a small quantity of ribonucleic acid (RNA)

Modification of histone proteins by acetylation will-

increase the transcription of target genes

(true or false) DNA polymerases "read" a parental strand 5' to 3' and synthesize a complementary antiparallel new strand 3' to 5'

false

DNA replication occurs during the ____________ phase of the cell cycle

synthesis

__________ enzyme unwinds and breaks the hydrogen bonds between nucleotides of 2 DNA strands for DNA replication

DNA helicase

DNA primase-

adds RNA primer to DNA strand for replication

Exonuclease-

removes RNA primers from the lagging strand

Okazaki fragments-

are the DNA synthesized on the lagging strand

Single-stranded DNA binding proteins-

prevent premature annelaing of the single-stranded DNA to double-stranded DNA

___________ is an enzyme that catalyzes the sealing of nicks (breaks) remaining in the DNA polymerase fills the gaps left by RNA primers

DNA ligase

__________________ enzymes relieve torsional stress in DNA by inducing reversible single-stranded breaks in DNA

topoisomerases

(true or false) Telomerase shortening is recognized as and is a part of the normal aging process

false

(true or false) Telomerase adds a series of DNA repeats to the leading strand. This addition allows the lagging strand to be completed by DNA polymerase

false

mismatch repair-

correcting the mismatches of normal bases that fail to maintain normal waston-crick base pairing

base excision repair-

correct the spontaneous depurination and spontaneous deamination that happens to bases present in DNA

Nucleotide excision repair-

removes UV light-induced DNA damage as well as DNA damage from environmental chemicals

Double-stranded DNA repair-

correct the severed strands of DNA caused by ionizing radiation, oxidative free radicals, or chemotherapeutic agents

(true or false) non homologous end joining is more accurate in repairing severed DNA than homologous recombination.

false