An Introduction to Genes and Genomes

BOGGLEWhen the timer begins, try to construct as many words

as possible using the given letters. You may go in any direction, but not diagonally.

Think & write quickly!!!

Genetic Code-our directions for inheritance (DNA)

NUCLEIC ACIDS• Nucleotide - monomer;

- phosphate group, 5 carbon sugar and nitrogenous base• Nucleotides covalently bind to form a nucleic acid• Nucleic acids store and transmit genetic information

4 Types of nucleotides (A-T/U-C-G) = endless # of different molecules2 Types of Nucleic Acids = DNA and RNA

Antiparallel=

“head to toe”

Building Activity

Central Dogma"the coded genetic information hard-wired into DNA is transcribed into individual transportable cassettes…each mRNA cassette contains the program for synthesis of a particular protein (or small number of proteins)." Chapter 1: The Dynamic Cell, of Molecular Cell Biology.

(NHGRI)

Gene Video• YouTube: http://www.youtube.com/watch?v=eOvMNOMRRm8&NR=1

Genes• Gene – a sequence of nucleotides

• Provides cells with instructions for making proteins• Usually 1000-4000 nucleotides in length• Then what is a chromosome??

• By controlling proteins, genes influence how cells, tissues, and organs appear

• Inherited appearances are called traits

• Some traits are controlled by one gene and some are controlled by many genes

Chromosomes and Genes

Chromosome Structure

Human Chromosomes

• Human cell = 23 pairs (46 total)• 23 chromosomes from mother (maternal)• 23 chromosomes from father (paternal)

• Pairs are called homologous pairs or homologues• Chromosomes 1-22 are autosomes• Chromosome pair 23 are the sex chromosomes, X

and Y chromosomes• Human egg and sperm, gametes, each contain 23

chromosomes - a haploid number (n) • All other cells, somatic cells, have two sets of

chromosomes – the diploid number (2n)

Karyotype• Chromosome 1 – largest• Chromosome 21 – smallest

DNA Replication Animations

http://www.youtube.com/watch?v=4jtmOZaIvS0

Semiconservative Replication

Prior to cell division, DNA replicates itself by semiconservative replication

Protein Function

Movement

Growth and Repair

NOT for energyStructure

Biochemical Control

Defense

Protein = “first or primary”

Transcription & Translation Video

transcription & translation animation

Protein Synthesis

• Genes within DNA are copied into messenger RNA molecules (mRNA) in a process called transcription

• mRNA molecules, which are exact copies of DNA, are deciphered into instructions for making a protein in a process called translation

DNA (deoxyribonucleic acid)

RNA (ribonucleic acid)

Deoxyribose Sugar

Double Stranded

Bases: A T C G

In the nucleus

Ribose Sugar

Single Stranded

Bases: A U C G

Leaves the nucleus

Transcription

Translation

• The ultimate function of a gene is to produce a protein.

• Translation is using the information in mRNA to synthesize a protein from amino acids.

Translation

Translation occurs in the cytoplasm of cells as a multi-stepprocess that involves several different of RNA molecules:

• Messenger RNA (mRNA) – an exact copy of a gene. Acts as a messenger by carrying the genetic code, from the nucleus to the cytoplasm where this information can be read to produce a protein.

• Ribosomal RNA (rRNA) – short molecules that make up ribosomes, organelles that are essential for protein synthesis. Ribosomes recognize and bind to mRNA and read the mRNA during translation.

• Transfer RNA (tRNA) – molecules that transport amino acids to the ribosomes during protein synthesis.