Introduction To Molecular Biology

Question 1

What are the typical features of a prokaryotic cell?

Answer 1

• unicellular organisms.
• found in all environments
• include bacteria and archaea
• without a nucleus; no nuclear membrane
• no membrane bound organelles
• usually one circular DNA molecule within the cytoplasm
• DNA is naked (no histone )
• Simple internal structure
• Cell division by simple binary fission

Question 2

What are the features of the eukaryotic cell?

Answer 2

• Found in animals, plants, fungi, and protists cell
• Has true nucleus: membrane bound nucleus
• Numerous membrane-bound organelles
• Eukaryotic genome is more complex than prokaryotic genome
  
  • Eukaryotic genome is distributed among multiple chromosomes;
• Eukaryotic nuclear DNA is linear;
  
  • Eukaryotic DNA is complexed with proteins called histones
• Complex internal structure
• Cell division by mitosis

Question 3

What are Archea?

Answer 3

• single called prokaryotes
• organisms without nucleus or membrane bound organelles
• Some aspects of their molecular biology are more like those of eukaryotes
  
  • For example, Bacteria contain a simple RNA polymerase made up of four polypeptides. However, both archaea and eukaryotes have multiple RNA polymerases made up of multiple polypeptides

Question 4

What is DNA?

Answer 4

The hereditary material in humans and almost all other organisms

Question 5

What is RNA?

Answer 5

A nucleic acid present in all living cells.

• It’s principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins
• In some viruses, RNA rather than DNA carries the genetic information

Question 6

An RNA molecule differs fromDNA…

Answer 6

• RNA has just one strand of nucleotides
• RNA has uracil in place of thymine
• RNA has ribose instead of deoxyribose

Question 7

What are the base pairing rules of RNA?

Answer 7

A:U

T:A

G:C

Question 8

Describe the flow of genetic information

Answer 8

• The sequence of bases in DNA is the template for mRNA, via transcription
• the template strand is always the same strand for a given gene
• During translation , the mRNA base triplets, called codons are read, by the translation machinery, in 5’ to 3’ direction
• Each codon specifies the amino acid (one of 20) to be placed at the corresponding position along a polypeptide which make up a protein

Question 9

What is a genome?

Answer 9

The entire genetic compliment of an organism, encoded in nucleic acids

Question 10

Describe prokaryotic genomes

Answer 10

• DNA concentrated in nucleoid

- Extrachromosomal as plasmid DNA

Question 11

Describe eukaryotic genomes

Answer 11

• nuclear genomes
• mitochondrial genomes
• chloroplast genomes

Question 12

What are chromosomes?

Answer 12

Threadlike structures of nucleic acids and protein found in living cells, carrying genetic information in the form of genes

It is an organized package of DNA

Question 13

How much chromosomes do humans have?

Answer 13

Each person has 23 chromosome pairs
-22 autosome pairs and 1 pair of sex chromosomes

This means 46 chromosomes in a human cells 23 from dad and 23 from mom

Question 14

What is an allele?

Answer 14

This is one of the possible alternative forms of a gene

For any chromosome pair, one allele is from mom and the other is dad