Ch 4: DNA, Chromosomes, and Genomes

Molecular Biology of the Cell. Alberts et al., 7th Ed.

What is hereditary information?

Genetic instructions passed from a cell to its daughter cells

What are the functions of protein?

• Proteins form cell structures

• Enzymes catalyze reactions

• Regulate gene expression

• Allows cells to communicate with each other

What is a human genome?

3.1 billion nucleotide pair that provides information for producing a human adult from a fertilized egg

What is a DNA strand?

One polynucleotide chain

What is the backbone of DNA made out of?

a five carbon sugar attached to a phosphate group

What are the bases of DNA?

• Adenine

• Cytosine

• Guanine

  • Thymine

What bond holds the sugar and phosphate together?

Phosphodiester bond which is a covalent bond

What bond holds the bases together?

Hydrogen bond

What charge does DNA have and why?

A negative charge because of the negative charge on the oxygen of the phosphodiester bond

What are base pairs?

Complementary base pairing; Purine pairs with pyrimidine

What is purine?

A two ring base

• Adenine

• Guanine

What is pyrimidine?

A single ring base

• Cytosine

• Thymine

• Uracil

What does antiparallel mean?

Due the polarity, one strand is oriented opposite to that of the other strand

What is a template?

Since one strand is exactly complementary to the partner strand, it can be the mold to synthesize a new complementary strand

What is the genetic code?

20 letter amino acid alphabet of proteins

What is gene expression?

The nucleotide sequence of a gene is converted to a nucleotide sequence of an RNA molecule and then to an amino acid sequence

What is a genome?

The complete information in an organism’s DNA

Where is nearly all the DNA in a eukaryotic cell stored?

The Nucleus

What is the nuclear envelope?

Two concentric lipid bilayer membranes outside the nucleus

What is the nuclear lamina?

A think feltlike mesh beneath the inner nuclear membrane

What are genes?

Information carrying units that specify all the RNA molecules and proteins made up by an organism

What do chromosomes contain?

Long DNA molecule and proteins that fold the DNA into a more compact structure

What are homologous chromosomes?

One chromosome from the mother and one from the father

What is the only nonhomologous chromosome?

The sex chromosomes in males, a Y chromosome from the father and X chromosome from the mother

How many chromosomes do humans have?

46

What is a karyotype?

The display of chromosomes at mitosis

What are noncoding genes?

Genes that do not produced proteins