dna and protein synthesis notes Flashcards
what are the 3 major functions of DNA?
controls cellular activities, DNA replication, and DNA mutations
DNA carries a ____
code
DNA controls ____
cellular activities
what are encoded wishing the DNA?
genetic instructions (the code)
what is DNA replication?
when DNA makes exact copies of itself, made to be passed onto other cells
explain how DNA mutation has changed species that live on earth?
different combinations of DNA sequences due to mutations and sexual reproduction explain the existence of all different species on earth
DNA is the source _____
of the unity of life
what did life most likely begin as?
a nucleic acid
what are the two types of nucleic acids?
DNA and RNA
the first form of life on earth is thought to be a self-replicating strand of what?
RNA
who discovered the first x-ray data for the DNA structure?
franklin in 1951
who discovered that DNA has a double helix?
james watson and francis crick (bad people)
1953
DNA and RNA are polymers of what?
nucleotides
what is a nucleotide composed of?
- a pentose (5 carbon) sugar (deoxyribose/ribose)
- a phosphate group
- a nitrogenous base
what are the two types of bases?
purines and pyrimidines
which base has a double nitrogen ring structure?
purines
which base has a single nitrogen ring structure?
pyrimidines
what are the two nucleotide bases of purines?
adenine and guanine
what are the three nucleotide bases of pyrimidines?
thymine, cytosine, uracil (RNA ONLY)
DNA is a _____ helix
double
what is linked together to form the double helix of DNA?
a sequence of nucleotides linked together
what are the strands of DNA composed of?
alternating molecules of deoxyribose and phosphate
what is attached to each deoxyribose unit in DNA?
a nitrogenous base
what can the double helix be described as?
a twisted ladder
what connects the two nucleotides to form the helix of DNA?
hydrogen bonds
what are the bases in DNA attached to?
the sugar molecules ( P and S )
what are the 4 bases in DNA?
adenine (A), thymine (T), guanine (G), cytosine (C)
what pyrimidine (letter) connects to the purine adenine (A)?
thymine (T)
what pyrimidine (letter) connects to the purine guanine (G)?
cytosine (C)
how many hydrogen bonds do adenine and thymine have in DNA?
2 H-bonds
how many hydrogen bonds do guanine and cytosine have in DNA?
3 H-bonds
what is chargaffs rule?
the number of purine bases equals the number of pyrimidine bases
T or F: the bases can be paired with any of the other bases in DNA
FALSE:
the bases may only be paired as A-T or T-A, G-C or C-G
T or F: the bases have to be in a certain order every time within the DNA
FALSE:
order does not matter, as long as they are paired correctly.
roughly how many pairs of bases are in the human body?
3 billion; about one meter in every human
where are the genes located in the cell?
on the chromosomes within the nucleus
roughly how many base-pairs are in a gene?
about 1000 DNA base-pairs