topic 14:Molecular genetics Flashcards
what does DNA stand for ?and explain what it is
Deoxyribonucleic acid. It is the genetic material which is found in the form of chromosomes in the nuclei of cells
what is plural for nucleus ?
nuclei
what is the name of bonds which nitrogenous bases have which connect them together?
hydrogen bonds
what is the rule of complementary base-pairing?and how many bonds do they form ?
Adenine with Thymin,there will be 2 hydrogen bonds formed. When guanine and cytosine bind, there will be 3 hydrogen bonds formed
each basic unit of DNA ,which is called a nucleotide,is made up of three elements,their shapes are circle,pentagon and square/rectangle .Identify these elements and how many sides does a pentagon have?
The circle is phosphate group,the pentagon is deoxyribose pentose sugar and the square/rectangle is nitrogenous base .The pentagon has 5 sides .
Describe the structure of DNA (5 points)
1.DNA consists of 2 antiparallel strands of polynucleotides which are coiled together in a double helix structure
2.each polynucleotide strand of DNA is made up of smaller basic units called nucleotides joined together, sharing a sugar-phoasphate backbone
3.In turn,each nucleotide is made up of 3 parts-A deoxyribose pentose sugar molecule,a phosphate group and a nitrogeneous base
4.There are 4 types of nitrogeneous bases-Adenine,Thymine,Guanine,Cytosine
5.Adenine always binds to Thymine and Guanine always binds to Cytosine,according to the rule of complementary base-pairing.Hydrogen bonds are formed between the complementary bases.When A and T bind,2 hydrogen bonds are formed.When G and C bind,3 hydrogen bonds are formed
how many pairs of chromosomes are there inside the nucleus of human non-sex cell
23 pairs
what form of genetic information is most condensed and coiled
Chromosomes
describe gene
each gene is one segment of a DNA comprising a specific sequence of nucleotide bases
Chromosomes,DNA,gene,chromatin,allele.Rank them in order from smallest to biggest
allele,gene,DNA,Chromatin,chromosomes
what is the function of gene
Each gene contains genetic information in the form of a specific sequence of nucleotide bases coding for
-a specific sequence of amino acids
-used to make up a specific polypeptide
-which is in turn,required to make up a specific protein
-which is required for a specific function
-every 3 bases on the gene codes for a specific amino acid
how does the gene cause the ribosomes to synthesise proteins?state the two processes and describe them
To synthesise proteins from DNA strand,the following 2 processes occur(this sentence is not important)
.Transcription to get mRNA
-DNA template strand is used to make a complementary messenger mRNA strand
-mRNA strand exits nucleus into the cytoplasm to the ribosomes
.Translation to get amino acids then polypeptide
-Ribosome reads the 1st codon(1 codon=1 set of 3 bases)on mRNA and gets the first amino acid from the various amino acids already present in the cytoplasm
-Ribosome reads the 2nd codon on mRNA and gets the second amino acid,and joins it to the first amino acid via formation of a peptide bond
-Ribosome continues to read the 3rd codon and continues until all the codons of the mRNA are read,and all the amino acids have been joined to form a polypeptide
a polypeptide formed consists of (1)______joined together by (2)__________
(1)amino acids
(2)peptide bonds
describe transcription to get mRNA(No need to memorise this ,but good to understand)
-DNA template strand is used to make a complementary messenger RNA strand
-mRNA strand exits nucleus into the cytoplasm to the ribosomes
describe translation to get amino acids then polypeptide which folds to form a protein(no need to memorise for this, but good to understand)
-Ribosome reads the 1st codon(1codon=1 set of 3 bases)on mRNA and gets the first amino acid from the various amino acids already present in cytoplasm
-Ribosome reads the 2nd codon on mRNA and gets the second amino acid ,and joins it to the first amino acid via formation of a peptide bond
-ribosome continues to read the 3rd codon and continues until all the codons of the mRNA are read,and all the amino acids have been joined to form a polypeptide
what does RNA stand for ?
ribo-nucleic acid
how does RNA differ from DNA
-instead of having Thymine,RNA has the nitrogeneous base called Uracil(U)
-Instead of existing as a stable long,double-stranded molecule like DNA,RNA is a shorter,single-stranded molecule and is more unstable
(the rest is not needed to know)
each gene only contains genetic information coding for one____________
polypeptide
what is the definition of transgenic organism
a genetically-modified organism which has taken in a foreign gene
definition of genetic engineering
the technique used to produce a transgenic organism by transferring one or more genes of interest from one organism into a recipient organism ,such that the transferred gene can be expressed
describe the process of transferring a gene from one living thing to another
The gene of interest wil be identified and isolated ,it will then be cut out using restriction enzymes,leaving “sticky ends”.Then,cut open a bacteria’s plasmid DNA which will be used as a vector,using the same restriction enzymes,this will leave complementary “sticky ends” to the gene of interest.The gene will be binded and sealed with the plasmid DNA to become one circular recombinant plasmid DNA.To introduce the recombinant plasmid into the bacteria ,apply temporary heat/electric shock to open up pores in the bacteria’s cell membranes and the recombinant plasmid DNA can now enter.
