Upgrade to remove ads
Only $35.99/year

Microbiology Fundamentals: A Clinical Approach, 2nd ed. by Cowan Chapter 8

Terms in this set (61)

Genetics
The study of inheritance, or heredity, of living things

Explores...
-transmission of biologic properties (traits) from parent to offspring
-the expression and variation of those traits
-structure and function of the genetic material
-how genetic material changes
Genomes
Sum total of genetic material of an organism

Most of the genome exists in the form of chromosomes

Some appear as plasmids or in certain organelles of eukaryotes

Genome of cells composed entirely of DNA

Genome of viruses can contain either DNA or RNA
Chromosome
Discrete cellular structure composed of a neatly packaged DNA molecule
Eukaryotic Chromosome
DNA wound around histones

Located in the nucleus

Linear appearance
Prokaryotic Chromosome
DNA condensed by supercoiling

Single, circular chromosome
Gene
Classical genetics definition: Fundamental unit of heredity responsible for a given trait in an organism

Molecular and Biochemistry definition: Site on the chromosome that provides information for a certain cell function

A certain segment of DNA that contains the necessary code to make a protein or RNA molecule

Segment of DNA that contains code to make a group of related proteins or RNA
Categories of genes
Structural genes code for proteins

Genes that code for RNA machinery used in protein production

Regulatory genes control gene expression
Genotype
Sum of all gene types

An organism's distinctive genetic makeup
Phenotype
Expression of certain traits (structures or functions)

All organisms contain more genes in their genotypes than are manifested in the phenotype at any given time
Size & Packaging of Genomes
Genome of E. coli...
-single chromosome containing 4,288 genes
-1 mm if unwound and stretched linearly; 1000 times longer than the cell
-takes up one-third to one-half of the volume of the cell

Human genome...
-25,000 genes on 46 chromosomes
-if all 46 chromosomes were unraveled and laid out end to end, it would measure 6 feet
Nucleotide
Basic unit of DNA structure

Phosphate, deoxyribose sugar, nitrogenous base

Covalently bond to each other in a sugar-phosphate linkage that becomes the backbone of each strand
-each sugar attaches in a repetitive pattern to two phosphates
-one attaches to the 5' (five prime) carbon and one attaches to the 3' (three prime) carbon
DNA code
Nitrogenous bases attach along a strand by covalent bonds at the 1' position of the sugar

Purines and pyrimidines join with complementary bases using hydrogen bonds

Pairing of bases dictated by the formation of hydrogen bonds between bases:
Adenine (A) always pairs with Thymine (T)
Guanine (G) always pairs with Cytosine (C)
DNA replication
Overall replication process is semi-conservative replication
careful orchestration of the actions of 30 different enzymes

Separate the strands of the existing DNA molecule, copying one strand and producing two complete daughter molecules

Each daughter molecule is identical to the parent in composition

Neither is completely new; one strand that serves as a template is an original parent of the DNA strand
Helicase
Unzipping the DNA helix

Break the hydrogen bonds holding the two strands together, resulting in two separate strands
Primase
Synthesizing an RNA primer
Recommended textbook explanations

Microbiology

1st EditionAnh-Hue Thi Tu, Brian M. Forster, Mark Schneegurt, Nina Parker, Philip Lister
384 explanations

Biology (Foundations Series)

1st EditionLevine, Miller
1,756 explanations

Biology

10th EditionJohnson, Jonathon Losos, Kenneth Mason, Peter H. Raven, Susan Singer
2,113 explanations

Campbell Biology

9th EditionJane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman
655 explanations