A1.2 Nucleic Acids

Similarity between different cells regarding their genes in one multicellular organism

Similarity between different cells regarding their genes in one multicellular organism

same type of genetic materials/ same DNA sequence

Differences between different cells regarding their genes in one multicellular organism

only use genetic code appropriate for their functions

Structure of nucleotides

• phosphate group

• Pentose

• nitrogenous base

To what carbon number is the phosphate group attached to one nucleotide?

Carbon 5 (5’)

To what carbon number is the phosphate group attached to between two nucleotides?

Carbon 3 (3’)

Type of bond between pentose and phosphate group

Covalent bond

What reaction between the phosphate group and the pentose sugar of nucleotides go through to form a polymer?

condensation reaction

Condensation reaction definition

reaction in which a small molecule (such as water) is REMOVED when synthesizing two molecules into a larger molecule

reason why nucleic acid polymers made of nucleotides are stable

covalent bonds are relatively strong

RNA nitrogenous bases

• Uracil

• Adenine

• Guanine

• Cytosine

우아! 거실

DNA nitrogenous bases

• Adenine

• Thymine

• Guanine

• Cytosine

At 거실

What structure and characteristics of RNA makes it different from DNA?

• Sugar: ribose sugar

• Nitrogenous base: Uracil

• Strand: single-stranded

• Shape: variety of shapes

What structure and characteristics of DNA makes it different from RNA?

• Sugar: deoxyribose sugar

• Nitrogenous base: Thymine

• Strand: Double-stranded

• Shape: double helix

What are the specific structures of DNA

• double helix

• two ANTIPARALLEL strands of nucleotides

  • each strand has complementary nitrogenous bases joined together by hydrogen bonds

complementary base pairing description

nitrogenous bases of DNA that always pair up with each other:
- Adenine - Thymine
- Guanine - Cytosine

Deoxyribonucleic Acid (DNA) definition

A molecule that provides and stores long-term genetic information for all organisms on Earth.

Where do mutations that influence evolution occur in?

DNA

Nitrogenous bases definition

Genetic messages which are codes for amino acids

Messenger RNA (mRNA) Definition

• synthesized in gene (area in DNA)

• leaves nucleus to represent the genetic information for protein synthesis

Transfer RNA (tRNA) definition

• a special gene of the DNA gives codes to the RNA type

• Transfers correct amino acids into a growing chain of amino acids.

  • amino acids have to be created into a chain in a specific order

Transcription definition

When code from DNA is decoded into mRNA

Translation definition

information from mRNA is decoded into protein

Ribosomal RNA (rRNA)

• special genes from the DNA give codes to this RNA

• code for creation of ribosomes

Adenosine triphosphate (ATP)

• single-nucleotide nucleic acid

• chemical energy

type of bond between nitrogenous bases

hydrogen bond

Why is complementary base pairing important?

• for DNA replication

  • when one DNA is separated into single strands, free nucleotides can bond with the nucleotides of the strands to form two identical DNA molecules

Triplet codon definition

sequence of three bases that represent a meaningful piece of information

What do the triplet codon code for?

one of the 20 amino acids

Number of triplet codon in a DNA

4³=64

Gene of DNA definition

one strand of DNA

Importance of directionality in DNA

• structure of nucleic acids

• functions of nucleic acids in DNA replication and RNA synthesis
  

What nitrogenous bases of DNA are purines

• adenine

• guanine

What nitrogenous bases are pyrimidins

• thymine

• cytosine

What is the effect when purines pair up with pyrimidins?

equal width between the nitrogenous base pairs ∴width remains constant throughout the length of the DNA

What is the importance of purines pairing up with pyrimidins?

stability of DNA molecule increases due to the constant width of it

number of chromosomes in a human cell

46

first step of DNA “packaging”

DNA molecule wraps around 8 histones; additional histone to hold structure together

Nucleosome definition

sequence of DNA that wraps around 8 histones

Second step of DNA “packaging”

Linker DNA links nucleosomes to other nucleosomes.

Linker DNA defintion

DNA that extends a nucleosome to connect with another nucleosome.

Third step of DNA “packaging”

stacking up of multiple nucleosomes; condense coiling around other proteins

Chromosome definition

“packaged” DNA

Outline the Hershey-Chase experiment

• Bacteriophages were grown in two cultures: radioactive phosphorus 32 and radioactive sulfur 35.

• bacteriophage infects E.coli

• inside infected E.coli, radioactive phosphorus was detected

why did Hershey and Chase use radioactive phosphorus 32?

Nucleotides, constituents of DNA, contain a phosphorus group

why did Hershy and Chase use radioactive sulfur 35?

Proteins contain a sulfur group.

Chargaff’s Rule

Number of adenine and thymine are same + number of guanine and cytosine are same

tetranucloetide theory

• nucleotides in repeating set units of four

• nucleotide give structure to chromosomes

What method did Chargaff’s experiment use?

Paper chromatography

what method did Hershey and Chase use?

Radioactive isotope labelling

Structure of purine

double-ring

Structure of pyrimidine

single-ring

Conserved genetic code reason

from a single-celled organism, DNA and RNA were used.
DNA for storage of genetic information and RNA to transfer that to the order of amino acids

Why can’t base pairings happen between purines and pyrimidines that do not follow the A-T or G-C pairing?

Hydrogen bonds cannot be formed