nucleic acids and protein synthesis
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NUCLEIC ACIDS AND PROTEIN SYNTHESIS. QUESTION 1. DNA. QUESTION 2. To store and transmit the genetic information that tells cells which proteins to make and when to make them. QUESTION 3. They form the structural units of cells and help control chemical processes within cells. - PowerPoint PPT PresentationTRANSCRIPT
NUCLEIC ACIDS AND PROTEIN SYNTHESIS
QUESTION 1
DNA
QUESTION 2
To store and transmit the genetic information that tells cells which proteins to make and when to make them
QUESTION 3
They form the structural units of cells and help control chemical processes within cells.
Question 4
The nucleotide. They are arranged in two long complementary chains.
Question 5A nitrogen-containing base, a sugar molecule called deoxyribose, and a phosphate group.
Question 6
Adenine, abbreviated A
Guanine, abbreviated G
Cytosine, abbreviated C
Thymine, abbreviated T
Purines: Adenine and Guanine. Have two carbon rings
Pyrimidines: Cytosine and Thymine. Have a single carbon ring.
Question 8
James Watson and Francis Crick in 1953.
Question 9
The alternating deoxyribose sugar and phosphate molecules which are linked together by covalent bonds.
Two Views of the DNA backbone
Sugars
Phosphates
The backbone is shown in yellow in this diagram. Notice that there are two backbones, one for each of the strands of nucleotides
Question 10
They are covalently bonded to the deoxyribose sugar and then to the complementary nitrogen base in the other strand by hydrogen bonds.
Hydrogen bonds
Backbone
Covalent bonds
Question 11
Guanine from one nucleotide strand will always pair with cytosine from the other strand using three hydrogen bonds and adenine from one strand will pair with thymine from the other using two hydrogen bonds.
Backbone
Two Three
Question 12
The process of copying DNA in a cell.
Question 13
The two nucleotide chains separate by unwinding, and each chain serves as a template for a new nucleotide chain.
Red color is the new strand. Blue color is the original strand.
Question 14
The point at which the two nucleotide chains separate
Replication Fork
Question 15
They separate the two complementary chains of nucleotides in the DNA molecule by moving along the molecule and breaking the hydrogen bonds between the complementary bases.
DNA Helicase
Question 16
Bind to a separated chain of nucleotides, move along the separated chain and assemble a new chain using free nucleotides in the nucleus and the separated chain as a template.
DNA Helicase
Polymerase
Polymerase
Question 17
The complementary nature of the two chains of nucleotides that make up the DNA molecule. If the original chain of nucleotides has a nitrogen base sequence of CATCAA the other assembled beside it would be GTAGTT.
DNA Helicase
Polymerase
Polymerase
Red color is the new strand,blue color the original strand. The red box is showing the complementary bases mentioned in the last slide.
Question 18
It proceeds in opposite directions on each original strand. Replication begins simultaneously at many points along one original strand and at just one point on the other original strand.
DNA Helicase
Polymerase
Polymerase
Polymerase
PolymeraseDirection
of Replication
Polymerase
Question 19
Two new exact copies of the original DNA molecule. Each molecule has one original strand of nucleotides and a copied complementary strand.
Original DNA
Original DNA strands opened up
Two new molecules of DNA each with one old and one new strand
Practice making a copy of DNA
Question 20
Replication is very accurate, only about one error in every 10,000 paired nucleotides.
Question 21
A mutation
Question 22
Enzymes that proofread DNA and repair errors
Question 23
A variety of agents, including chemicals, ultraviolet radiation and other forms of radiation.
Question 24The transfer of genetic information from the DNA in the nucleus to the site of protein synthesis on the ribosomes.
Question 25
The nucleotide.
Question 26The sugar in RNA is ribose in DNA it’s deoxyribose. RNA has the nitrogen base Uracil (U) instead of Thymine as in DNA
Question 27
Messenger RNA (mRNA) - carries genetic information from DNA in the nucleus to the ribosome.
Ribosomal RNA (rRNA), combines with proteins to make up the two subunits of a ribosome
Question 27 (continued)
Transfer RNA (tRNA) -each binds to a particular amino acid and brings it to the ribosome
Question 28The process by which genetic information is copied from DNA to mRNA
Question 29
RNA polymerase. Makes RNA copies of specific sequences of DNA
Question 30A specific region of DNA that marks the beginning of that part of the DNA chain that will be transcribed.
The DNA unwinds and the RNA polymerase binds at a particular site on the DNA. The initial binding
site is called the "promoter region".
Question 31
That portion of the DNA molecule (only one of the two nucleotide strands) that is copied by RNA polymerase.
Template strand
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DNA
Question 32
The nitrogen base sequence on the template chain and complementary base pairing by RNA polymerase.
DNA
Template strand
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Nitrogen base sequence on DNA
Complementary base pairing on mRNA
Question 33
Uracil Template strand
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DNA
Question 34The termination signal - a specific sequence of nucleotides on the template that marks the end of a gene.
Template strand
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DNA
Question 35
The RNA polymerase
Template strand
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DNA
Termination signal
Question 36Transcripts - different types of RNA molecules including mRNA, tRNA, and rRNA. The mRNA may have further processing occur. Noncoding regions called introns are removed and the remaining coding regions called exons are spliced together.
Question 37
Amino Acids. Twenty different kinds.
Question 38
It’s three dimensional structure, which is determined by its amino-acid sequence.
Levels of protein structure that determine the function of a protein.
Question 39
Triplets of nucleotides in mRNA that determine the sequence of amino acids in proteins
Genetic Code
Question 40
A sequence of three nucleotides on a mRNA molecule. It codes for one specific amino acid. There are 64 codons.
Genetic Code
codons codonscodons codons
start
Question 41
The codon that causes a ribosome to start translating an mRNA molecule into a protein. It is always the nitrogen base sequence AUG. The codons that cause translation to cease. There are three.
start
Question 42
That all organisms are related.
Question 43
The process of assembling proteins from information encoded in mRNA. It begins when a mRNA molecule leaves the nucleus and migrates to a ribosome.
Question 44
The ribosome.
Question 45
tRNA molecules.
Question 46A sequence of three nitrogen bases on the tRNA molecule that are complementary to a codon on a mRNA molecule. It actually pairs with the codon on
mRNA.
Question 47The complementary base pairing between codons on mRNA and anticodons on
tRNA
anticodon
codons
Question 48Composed of rRNA and proteins. Make up 2 subunits. Found free in the cytosol and attached to the endoplasmic reticulum.
Question 49
Ribosomes found free in the cytosol produces proteins used inside the cell. Those attached to the E.R. produce proteins used in the cell membrane or outside of the cell.
Question 50One site holds a mRNA transcript so its codons can be read by tRNA. The other two sites (P and A sites) hold tRNA molecules so that their attached amino acids can be bonded to the growing chain.
mRNA holding site
Question 51
Methionine. Only initially. It may be removed later.
mRNA binding site
Start codon
Question 53
Yes. Many can. They may form a chain known as a polysome.
transcript
Review of Protein Synthesis: Transcription and Translation