Question Set 2 What is the Central Dogma of Biology Complete

Question Set 2

What is the Central Dogma of Biology?

Complete the following chart:

Monomers

Macromolecule (Polymers)

Purpose

Fatty acids

Fats, lipid membranes

Polysaccharides

Structure, energy storage

Proteins (polypeptides)

Nucleic acids (DNA, RNA)

Describe the \"amphiphilic\" nature of phospholipids, and how this facilitates the structure of the plasma membrane

Name three possible functions for proteins that are embedded in a membrane.

Name the steps of the cell cycle. What happens in each?

In reference to the cell cycle, what is a checkpoint? Give some examples of triggers of cell cycle arrest.

In the context of cell signaling, define: autocrine, homocrine, paracrine, and endocrine.

Monomers	Macromolecule (Polymers)	Purpose
Fatty acids	Fats, lipid membranes
	Polysaccharides	Structure, energy storage
	Proteins (polypeptides)
	Nucleic acids (DNA, RNA)

Solution

Central Dogma of Biology

The central dogma of biology refers to the flow of genetic information from DNA to mRNA to protein. It relates to the expression of mRNA from the genes which are translated in the cytoplasm. Since DNA is very important hereditary molecule, the cell copies the message in the form of RNA and keeps DNA protected.

Monomers

Macromolecule (Polymers)

Purpose

Fatty acids

Fats, lipid membranes

Energy source, reserve food materials, heat insulation, membrane structure

Monosaccharides

Polysaccharides

Structure, energy storage

Amino acids

Proteins (polypeptides)

Energy source, structure formation, transport of molecules (iron), storage of molecules (ferritin), signaling molecules, hormones

Nucleotides

Nucleic acids (DNA, RNA)

Hereditary material, signaling molecules, energy molecules (ATP)

Describe the \"amphiphilic\" nature of phospholipids, and how this facilitates the structure of the plasma membrane

Answer: Amphiphilic molecules are those molecules having both polar and non-polar groups. For phospholipids, they have polar phosphate hydrophilic group and two long fatty acid hydrophobic non-polar tails. Due to this amphiphilic nature they an important part of membranes because the polar group is oriented to the polar hydrophilic sides (extracellular side and cytosol) and hydrophobic region of hydrophobic region (fatty acid tails). It is this amphiphilic nature that makes it as a good barrier.

Name three possible functions for proteins that are embedded in a membrane

Name the steps of the cell cycle. What happens in each?

The cell cycle or cell-division cycle is the cycle that takes place in a cell and causes the cell to divide and duplicate of its DNA to produce two daughter cells

G0 phase (Quiescence):

                 Cell continues to grow

Mitotic phase (Chromosome separation)

In reference to the cell cycle, what is a checkpoint? Give some examples of triggers of cell cycle arrest.

These are the points which are utilized by the cell

In the context of cell signaling, define: autocrine, homocrine, paracrine, and endocrine.

Endocrine Hormones: These hormones are secreted into the blood. These hormones are carried by blood mostly and also by tissue fluids to the cells they act upon. e.g. insulin and glucagon secreted by pancreas into blood and these hormones regulate blood sugar levels

Exocrine Hormones: Some glands like sweat glands release a secretion through a duct to the surface of an organ.

Autocrine Hormones:

Monomers	Macromolecule (Polymers)	Purpose
Fatty acids	Fats, lipid membranes	Energy source, reserve food materials, heat insulation, membrane structure
Monosaccharides	Polysaccharides	Structure, energy storage
Amino acids	Proteins (polypeptides)	Energy source, structure formation, transport of molecules (iron), storage of molecules (ferritin), signaling molecules, hormones
Nucleotides	Nucleic acids (DNA, RNA)	Hereditary material, signaling molecules, energy molecules (ATP)