Macromolecules, DNA vs RNA

4 major macromolecules:

• carbohydrates

• lipids

• proteins

• nucleic acids

Each macromolecule has:

• monomers or building blocks,

• unique bonds,

• and a clear biological purpose

Name the monomer, polymer, bond, structure, and function of Carbohydrates.

• Monomer: glucose, fructose, galactose

• Polymer: glycogen, starch, cellulose

• Bond: glycosidic bond

• Structure: rings of carbon, hydrogen, and oxygen (ratio of 1:2:1)

  • ends in -ose (fructose, galactose, etc)

• Function → quick energy from glucose; energy storage from glycogen and starch; plant cell walls from cellulose

Name the monomer, polymer, bond, structure, and function of Lipids.

• Monomer: fatty acids + glycerol

• Polymer: triglycerides, phospholipids, steroids

• Bond: ester bond

• Structure: long hydrocarbon chain (nonpolar/hydrophobic)

• Function → long-term energy storage, cell membrane, hormones, insulation

Name the monomer, polymer, bond, structure, and function of Proteins.

• Monomer: amino acids

• Polymer: polypeptide → protein

• Bond: peptide bond

• Structure:

  • Amine group (NH₂)

  • Carboxyl group (COOH)

  • R-group (determines properties)

• Functions → enzymes, transport (hemoglobin), structure, hormones, movement

Name the monomer, polymer, bond, structure, and function of Nucleic acids.

• Monomer: nucleotide

• Polymers: DNA, RNA (nucleic acids)

• Bond: phosphodiester bond

• Structure: 

  • Phosphate group

  • Pentose sugar (ribose, deoxyribose)

  • Nitrogenous bases (A, T, G, C, U)

• Function → store and transmit genetic info, make proteins (mRNA, tRNA, rRNA)

What are the two types of nucleic acids?

• Deoxyribonucleic acid (DNA):

  • double-stranded helix, with two strands running antiparallel

  • strands are held together by hydrogen bonds between the complimentary bases → A=T and C=G

• Ribonucleic acid (RNA):

  • one-stranded and can fold into other shapes due to base pairing within the same strand → A=U and C=G

  • critical in protein synthesis + gene regulation

What is the main difference in the structure between Deoxyribonucleic acid and Ribonucleic acid (DNA & RNA)?

The sugar in DNA is deoxyribose and in RNA, it’s ribose. Meaning, the difference lies in the presence of an oxygen atom.

Deoxy = one less oxygen

What are the three types of RNA and their function?

• mRNA → a messenger that carries genetic code from DNA to ribosome (“blueprint or instructions for protein”)

• tRNA → a transferer that brings amino acids to ribosome and matches anticodon to codon (carries amino acids)

• rRNA → is ribosomal, or makes up ribosomes. the site of protein synthesis

When, where, and what happens during DNA replication?

DNA replication occurs before cell division in the nucleus

• (before mitosis/meiosis, during S phase of interphase)

What happens?

1. DNA unzips by helicase

2. DNA polymerase builds new complimentary strands

3. Produces two identical DNA molecules

Replication involves one old strand and one new strand

What is transcription, where and what happens during transcription?

The purpose of transcription is to make mRNA from DNA. This occurs in the nucleus.

What happens?

1. RNA polymerase reads DNA

2. Builds mRNA

Product: mRNA leaves the nucleus, enters the cytoplasm, and to ribosome

What is translation, where and what happens during translation?

Translation builds protein from mRNA in the ribosomes in the cytoplasm or rough ER.

• mRNA → instructions

• tRNA → carries amino acids

• rRNA → ribosome

1. Ribosome reads mRNA codons (3 bases)

2. tRNA brings matching anticodon with amino acid

3. Amino acids link → form polypeptide / protein

Chromatin is …

loose DNA in nucleus

Chromosomes are …

condensed DNA that forms during division (prophase)

A chromatid is …

one of the two identical halves of a duplicated chromosome

A gene is …

a DNA segment coding for a protein

An allele is …

a version of a gene

A genome is …

all DNA in an organism

Insertion or Deletion Mutation

these mutations change DNA bases by adding or removing a base respectively 

Silent mutation

a change in the sequence of nucleotides that does not affect the amino acid or function of the protein

Frameshift mutation

a genetic mutation that occurs due to the insertion or deletion of nucleotides in DNA sequence and alters the reading frame of the codons

(changes every codon after the mutation)

Missense Mutation

occurs when a single nucleotide base in DNA is swapped for another one, resulting in a different codon and a different amino acid

Nonsense mutation

also a change in one DNA base pair, but instead of substituting one amino acid for another like missense, the altered DNA sequence prematurely builds a protein → premature shortened protein with no function