AND HIGH YIELD TOPICS REVISION PACK A+
◉ Identify this part of the chromosome Answer: p-arm
◉ Identify this part of the chromosome Answer: q-arm
◉ What are chromatids? Answer: one of two identical "sister" parts
of a duplicated chromosome
◉ What are the 4 phases of the cell cycle? Answer: G1, S, G2, Mitosis
◉ What is the purpose of Mitosis? Answer: cell regeneration,
growth, and asexual reproduction
◉ What is the purpose of Meiosis? Answer: produce gametes for
sexual reproduction
◉ How does meiosis differ between males and females? Answer:
Meiosis in males makes four sperm, while meiosis in females makes
one egg and three polar bodies. This is so the extra chromosomes
have a place to go. Polar bodies eventually disenegrate.
,◉ What are histones? Answer: Proteins that pack DNA into
condensed formed; Because eukaryotic DNA is so long, histones help
provide structural support by compacting the DNA
◉ How does acetylation/deacetylation help package and unpackage
DNA along nucleosomes? Answer: When acetyl groups are added to
cytosine, this makes the chromatin more compact
(heterochromatin)
When deacetylase removes these acetyl groups, this makes the
chromatin less compact (euchromatin)
◉ Why are heterochromatin inaccessible for transcription? Answer:
heterochromatin are densely packed so they are too compact for
DNA Polymerase 3 to access the DNA. Thus, the template strand can
not be accessed for transcription
◉ What is the Central Dogma? Answer: DNA (replication) -> RNA
(transcription) -> Protein (translation)
◉ What are the names and function of the three basic elements of a
gene? Answer: promoter- where initiation begins; the sigma factor
binds to a strand of DNA and clips and untwists to make a
transcription bubble)
, RNA-coding sequence- the sequence that actually gets transcribed;
3'-5' strand
terminator- marks the end of a gene
◉ What ingredients are necessary for RNA transcription in
prokaryotes? Answer: RNA Polymerase (A holoenzyme the binds
and unwinds DNA via its sigma factor), initiation factors,
◉ Where does transcription occur? Answer: the endoplasmic
reticulum via ribosomes
◉ What direction is RNA polymerized? Answer: RNA is polymerized
in a 5' to 3' direction
◉ Describe the differences between the template strand and the
non-coding strand in transcription for prokaryotes (including the 5'
and 3' orientation of both) Answer: The non-coding template strand
is in a 5'-3' direction and is ignored during transcription
The template strand is in the 3'-5' direction and is used to synthesize
the transcript
◉ What are the two types of terminators used in prokaryotic
transcription? Answer: Rho-dependent : Rho helicase gets added to
the transcript and clips the RNA