BIOL 120- Chapter 8 (part 1)- Molecular Biology

What are the four characteristics of genetic material?

Replication, storage of information, expression of information, variation by mutation.

What did early studies indicate about the location of genetic material?

Genetic material resides in the nucleus and consists of proteins and nucleic acids.

Why did geneticists favor proteins over DNA until the 1940s?

Proteins were more abundant and diverse.

What did experiments reveal about DNA in body cells and gametes?

Body cell DNA amount is constant, while gametes are reduced to half.

What was the main finding of Frederick Griffith's experiment?

DNA from virulent bacteria transformed non-virulent bacteria into virulent forms.

What type of bacteria did Griffith use in his experiment?

Streptococcus pneumoniae.

What was the outcome when living Type R bacteria were injected into mice?

The mice survived, indicating Type R is non-virulent.

What happened when living Type R and heat-killed Type S bacteria were injected together?

The Type R bacteria were transformed into virulent Type S cells.

What did the Hershey-Chase experiment demonstrate?

DNA, not proteins, is the hereditary material that enters host cells.

What components make up a nucleotide?

A nitrogenous base, a pentose sugar, and a phosphate group.

What are the two types of nitrogenous bases?

Purines (Adenine, Guanine) and Pyrimidines (Cytosine, Thymine, Uracil).

How are nucleosides and nucleotides named?

According to the specific nitrogen base they contain.

What is the structure of RNA compared to DNA?

RNA is generally a single strand, while DNA is a double-stranded helix.

What are the three types of RNA and their functions?

mRNA (carries genetic information), tRNA (transfers amino acids), rRNA (forms ribosome structure).

What did Chargaff's rules state about DNA composition?

The amount of adenine equals thymine (A=T) and the amount of cytosine equals guanine (C=G).

Who proposed the double-helix structure of DNA?

James Watson and Francis Crick in 1953.

What is the significance of the phosphodiester bond in DNA?

It links nucleotides together, forming the DNA backbone.

What is the directionality of DNA strands?

The strands run in opposite directions, referred to as antiparallel.

What is the role of hydrogen bonds in DNA structure?

They connect the nitrogenous bases of the two strands.

What is the function of messenger RNA (mRNA)?

It carries information for protein synthesis as a sequence of codons.

What is the role of transfer RNA (tRNA)?

It acts as an interpreter between nucleic acids and proteins, picking up specific amino acids.

What is ribosomal RNA (rRNA)?

The most abundant type of RNA, which forms the structure of ribosomes.