Genes And Proteins Flashcards
is a large molecule that is consists of one or more polypeptide chain.
Protein
is a series of amino acids that are joined together by a polypeptide bond
polypeptide
are substances that catalyzes or speed up the rate of a chemical reaction.
Enzymes
properties of enzymes largely depend on their ___
amino acid sequence
Amino acid structure
Amine group, Hydrogen, carboxyl and R-group
is a side chain which determines the type of amino acid
r-group
for the proper functioning of enzyme, it must be of ____ and is
___.
the right kind; assembled in the right order
not all amino acid substitution leads to a ___
disease
Relationship between genes and enzymes was first suggested by ___, an
English physician, in 1902
Archibald Garrod
Garrod’s concept about the Relationship between genes and enzymes was developed as a result of his study on a disease called .
alkaptonuria
is a recessive trait that causes arthritis
Alkaptonuria
The urine of the affected person
turns black upon exposure to the air.
Alkaptonuria
Alkaptonuria is accompanied by serious physical and mental ___ (mean IQ – ___).
retardation; 65
In the case of alkaptonurics, they cannot metabolize ___ because they
lack the enzyme ___
homogentisic acid; homogentisic acid oxidase.
formulated the One Gene-One Enzyme Hypothesis
Beadle and Tatum
WHat does One Gene-One Enzyme Hypothesis state? (2)
(a) every gene controlled a particular enzyme
(b) the final product of the metabolic process is affected by stepwise succession of enzymes.
it means that, there is a one is to one correspondence between genetic mutation and the lack of specific enzyme requires for pathway.
One Gene-One Enzyme Hypothesis
the one controlling the synthesis of protein through the RNA
DNA
shows the flow of information in the biological systems
central dogma of molecular biology
DNA is produced from the RNA
reverse transcription
refers to the transfer of genetic
information from the nucleotide sequence of the DNA to the nucleotide sequence of the RNA
Transcription
Steps involved in the transcription (2)
- Uncoupling of the double stranded DNA molecule.
- Synthesis of RNA along one DNA strand
Synthesis of RNA along one DNA strand uses the catalyst:___
RNA polymerase
Once the RNA is synthesized, it will move from the ___ to __.
nucleus, cytoplasm
Types of ribonucleic acid (RNA (3)
mRNA
tRNA
rRNA
type of rna that carry the instruction for protein synthesis from the DNA (nucleus) to the ribosomes (cytoplasm)
Messenger RNA or mRNA
this rna brings the activated amino acids to the mRNA
Transfer RNA or tRNA
this rna is incorporated in the ribosomes
Ribosomal RNA or rRNA
features of transcription (4)
1.) Involve only certain regions of DNA
2.) Transcription is the major point of control of gene expression
3.)RNA synthesis occurs in a 5’ to 3’ direction.
4.)Transcription consists of three events (initiation, elongation, and termination)
DNA sequences that code for RNA
Coding regions
do not code for a gene product
Noncoding regions
refers to the synthesis of a polypeptide chain using the genetic
instructions from the mRNA.
Translation
Steps involved in translation (7)
a. DNA is transcribed to mRNA in the process of transcription.
b. The mRNA moves to the cytoplasm and becomes associated with ribosomes.
c. Different RNA’s in the cytoplasm pick up the amino acid and bring them in the ribosome as they move along the mRNA.
d. tRNA couples briefly with the mRNA (complementary to RNA bases) in the ribosomes.
e. Ribosomes move along the mRNA, adding amino acids to the polypeptide chain.
f. As each tRNA donates its amino acid to the growing polypeptide chain, it uncouples from the mRNA. It then moves away from the cytoplasm to pick up more amino acids.
g. Once the tRNA completed a peptide chain, it will be release from the ribosomes.
RNA polymerase binds to a sequence of DNA called the ___,found near the beginning of a gene.
promoter
Sequences called ___ signal that the RNA transcript is complete
terminators
is very important in decoding the DNA and RNA sequences into amino acids
Genetic code
is a collection of base triplets of DNA and RNA carrying the genetic
information.
Genetic code
DNA messages can be interpreted by using the ___
coding system
Decoding of mRNAs is being done by reading the nucleotides
in group of three, called __
codon
important features of codon (4)
a) They specify an amino acid.
b) Termination or stop codons mark the end of protein synthesis.
c) The codon AUG, which codes for methionine, marks the beginning of protein synthesis
d) The mRNA codons are read from 5’ to 3’ direction. They specify the order of amino acids from the N-terminus to C-terminus
Features of Genetic Code (5)
- Genetic Code is triplet.
- Genetic Code is degenerate/redundant/repetitious
- Genetic Code is non-overlapping
- Genetic Code is universal
- There are three nonsense codons
All amino acids are represented by several codons except __ and __
methionine AUG; tryptophan UGG.
Codons for same amino acid usually differ in third position only is based from what hypothesis?
Third Base Degeneracy Wobble Hypothesis
The __ bases are critical parts of the codon
first two
__, __, and __ called terminator or non-sense codons since they terminate the
amino acid chain in the synthesis protein.
UAG, UAA, UGA
