chapter 7 Flashcards
What are the two types of nucleic acid?
DNA and RNA
What are the 3 prime (3’) ends?
the end of a nucleic acid strand terminating at the third carbon of a sugar molecule
What are the 5 prime (5’) ends?
the end of a nucleic acid strand terminating at the fifth carbon of a sugar molecule
Which bases in DNA and RNA are complimentary?
DNA: A-T, C-G
RNA: A-U, C-G
Which bases are purines and pyrimidines
Purines: A and G
Pyrimidines: C and T
what is the structural significance of these bases?
purines: two rings
pyrimidines: one ring
What type of bond holds complementary bases together?
hydrogen bond
What is an organism’s genome?
all the genes an organism possesses
What are chromosomes
a DNA molecule wrapped around proteins
what are genes
a sequence of DNA
What is the “central dogma” of biology?
DNA-RNA-Protein
What are transcription and translation?
Transcription: DNA-RNA
Translation: RNA-Proteins
Where do these processes occur in eukaryotic cells?
Transcription: nucleus
Translation: ribosomes
what is the difference between DNA and RNA in terms of their sugar
Deoxyribose sugar in dna
ribose in rna
what is the difference between DNA and RNA in terms of their nucleotide bases
DNA has thymine
RNA has Uracil
what is the difference between DNA and RNA in terms of their form
DNA is double stranded
RNA generally single stranded
what is the difference between DNA and RNA in terms of their functions.
DNA: stores RNA
RNA: Makes Proteins
What are the three types of RNA involved in the synthesis of proteins, and what are their specific functions?
mRNA: Messenger RNA= Delivers a copy to ribosomes
rRNA: Ribosomal RNA= makes up ribosomes
tRNA: transport RNA= delivers amino acids
What are the three steps of transcription?
initiation, elongation, and
termination
What generally occurs during initiation
RNA polymerase binds to and unzips DNA
What generally occurs during elongation
RNA polymerase reads the DNA strand and adds complementary nucleotides.
What generally occurs during termination
RNA polymerase detaches from the DNA and releases RNA strand
What are the functions
of RNA polymerase?
opens double helix and dna can be copied into the language of RNA
What are the template strand
the strands that transcribed
What are the promoter
where transcription begins
What are the template terminator?
where transcription ends
What are the cap and tail?
The group at the beginning (5’ end) is called a cap, while the group at the end (3’ end) is called a tail.
What are two functions of the 5’ cap and 3’ poly-A tail?
They protect mRNA and help ribosomes attach to proteins
What are introns and exons, and which is
removed before translation?
introns: noncoding regions (removed)
Exons: coding regions
what are the genetic code
the way cells read rna to know what protein to assemble
codons?
a triplet of mRNA bases that specifies a particular amino acid or a “stop” signal
What are the three steps of translation? And what happens?
initiation: translation begins
elongation: Ribosomes move along mRNA attaching amino acids to polypeptides
and termination: Comes to a stop
what is gene regulation
How to control the expression of genes
what is an operon
group of genes that controls the transcription of the entire group of genes
what are the operator and repressor
operator: the on-off switch
repressor: blocks transcription
What is the function
of lac operon?
it breaks down lactose by making enzymes
In the absence of lactose, does transcription of genes occur?
no
In the presence of lactose,
does transcription of genes in the operon occur?
yes
What is the purpose of the proteins produced?
to break down lactose if its available
