Campbell Biology, Chapter 16 and 17 Flashcards
What are Bacteriophages
Also known as Phages, Bacteriophages are viruses that infect bacteria
What is the semi conservative model of DNA
One DNA strand can create another complementary strand through replication
What are Helicases
enzymes that untwist the double helix at the replication forks
What are replication forks
Areas where replication of DNA occurs
What is topoisomerase
enzyme that helps relieve this strain by
breaking, swiveling, and rejoining DNA strands.
What is Primase
Enzyme that synthesizes RNA primer
What are DNA polymerases
enzymes responsible for synthesizing new DNA strands
Why is RNA Primer required in Replication of DNA
DNA polymerase cannot synthesize DNA by itself, RNA primer provides a starting point for DNA polymerase to begin adding DNA nucleotides.
At the start of a DNA strand, what is found
5 carbon sugar and phosphate group
At the end of the DNA strand, what is found
3 Carbon sugar and Hydroxyl Group
Where does the energy required for DNA synthesis found
triphosphate group
DNA strands are antiparallel, what does that mean
the 2 strands of DNA that make up a DNA double helix run in opposite directions
At which end can DNA polymerase add Nucleotides to
3 prime end
What is a telomere
a region of repetitive DNA sequences at the end of a chromosome. Telomeres protect the ends of chromosomes from becoming frayed or tangled.
What is telomerase
adds nucleotides onto a telomere
What happens when telomere is shortened
cell division is limited
Describe DNA in bacteria
single, circular, double-stranded DNA molecule
What is chromatin
a mixture of DNA and proteins that form the chromosomes found in eukaryotic cells
What is a nucleosome
basic unit of chromatin, consisting of DNA wrapped around a core of Histone Proteins
What is Euchromatin and Heterochromatin
Euchromatin is loosely condensed nucleosomes and Heterochromatin is heavily condensed nucleosomes
Difference between Euchromatin and Heterochromatin
euchromatin allows genes to be expressed while heterochromatin prevents them from being expressed
Where does translation occur
Cytoplasm, specifically the ribosomes
Where does Transcription occur
Nucleus
What is the primary Transcription
The initial RNA transcript produced from any gene
1 codon codes for how many amino acids
1 type of amino acid
How many of the 64 possible codons code for amino acids
61
How many of the 64 possible condons code for stop codons, that terminate translation
3
What is the promoter in DNA
The DNA sequence where RNA polymerase binds and initiates transcription.
What is the Terminator in DNA
The DNA sequence that signals the end of transcription.
Additions to Pre-mRNA to prepare it for translation
Addition of modified guanine nucleotide to the 5’ end of the pre-mRNA, addition of a long string of adenine nucleotides added to the 3’ end of the pre-mRNA, and Removal of non-coding sequences (introns) and joining of the coding sequences (exons).
What are introns and extrons
extrons are coding regions and introns are non-coding regions in genes
What are Ribozymes
RNA molecules that act as catalysts
What is alternative splicing
a cellular process that allows a single gene to produce multiple proteins with different functions
What is tRNA
small RNA molecule that acts as a link between messenger RNA (mRNA) and amino acids to synthesize proteins
What is the main structural and functional component of the ribosome.
rRNA
Ribosome function
translation of mRNA into protein, provide binding sites for mRNA and tRNA
is a Ribosome a Ribozyme
yea, as ribosomes acts as the catalyst for peptide bond formation,
What is an anticodon
a sequence of three nucleotides in a transfer RNA (tRNA) molecule that pairs with a complementary codon in a messenger RNA (mRNA) molecule during protein synthesis
Proteins created by free ribosomes(ribosomes in the cytoplasm not bounded) go where
cytosol
Proteins created by bound ribosomes(ribosomes bounded to the nucleus and rough ER) go where
endomembrane system or secretion
