intro to Molecular bio

Question 1

what is molecular biology

Answer 1

field of science studying the chemical structures & processes that involve the basic units of life( molecules)

there are many molecules but the term is usually used to describe the study of nucleic acids

Question 2

why study molecular biology

Answer 2

nucleic acids form the information of hereditary genes

the sequence of nucleotides is the basis for normal & pathological traits in all species

• provides info to what is happening
• provides info to predict what could happen

Question 3

DNA

Answer 3

A nucleic acid that stores information
DNA is inherited

has a deoxyribose sugar, a phosphate group & base pairs ( adenine, tyrosine, guanine & cytosine)

usually double stranded

Question 4

RNA

Answer 4

there are many types
- can serve as an intermediate for protein production ( coding RNA)
- can serve a direct biological function ( non coding RNA; ncRNA)
RNA is transcribed from DNA

has ribose sugar, a phosphate, & base pairs ( Adenine, uracil, guanine & cytosine )

Question 5

gene

Answer 5

segment of DNA that encodes for a product with a biological function
- products are either proteins or RNA

Question 6

meaning of an expressed gene

Answer 6

when the information in a gene has been used by the cell to make a gene product

“switched on “

Question 7

amino acids

Answer 7

proteins are made up of amino acids

• each amino acids is encoded by a triplet nucleotide code called a codon
• the human genetic code compromises 64 codons which encode for 21 amino acids & 3 stop codons
• mRNA codons are read by anticodon regions of transfer RNA ( tRNA)

Question 8

tRNA

Answer 8

transfer RNA brings the corresponding amino acid to the growing polypeptide chain

Question 9

ribosomes

Answer 9

the polypeptide chain is synthesized by ribosomes which are macromolecular complexes containing ribosomal RNA ( rRNA) & a protein component

Question 10

transcription

Answer 10

taking information from a gene ( DNA) to an RNA molceule

Question 11

Translation

Answer 11

info in the mRNA molecule is used to make a protein

• mRNA sequence forms an amino acid sequence
• occurs on the cytoplasmic ribosomes

Question 12

Genome

Answer 12

complete set of chromosomes

total complement of hereditary information

Question 13

genetic code

Answer 13

complete list of nucleotide codons & the amino acids or actions for which they “code”

Question 14

human cells

Answer 14

contain 2 full copies of the haploid human genome organized into 23 pairs of chromosomes to form diploid genome

• one full set of chromosomes is inherited from each parent
• human genomes has 2 copies of each gene - terms alleles*

Question 15

chromosome

Answer 15

highly ordered structure of a single DNA molecule with specialized structural features including one centromere & two telomeres

Question 16

Allele

Answer 16

Alternative version of a gene at a given location ( locus) along a gene

• you get 2 alleles of each gene ( one from each parent)
• if the 2 alleles are the same, the individual is homozygous for that gene
• if the 2 alleles are different, they are heterozygous for that gene

Question 17

Genotype

Answer 17

primary nucleotide sequence of the two gene alleles

genetic makeup - genotype codes for the phenotype

Question 18

Phenotype

Answer 18

expressed function of biological effect of the gene product

observable physical or biochemical characteristics of an individual

Question 19

Human disease - genotyping or phenotyping

Answer 19

human disease can be studied at the genetic level through determination of the allelic sequence of a gene by genotyping

or at the functional level by phenotyping
ex of phenotyping
- enzyme concentration or activity
- ABO blood groups
- electrophoretic mobility of hemoglobin variants
- RNA expression levels

choice of genotyping or phenotyping for making a diagnosis depends on the specific diagnostic application & the strength of association between a genotype & its sequential phenotype