Bio EOC Cram

Chapters 12-20

Ch 12 - DNA

Scientists - Griffith - transformation = process in which one bacteria takes the

characteristics of another (takes in genes)

Avery - added enzymes to destroy organic

compounds, but not DNA trans. - added DNA-destroying enzymes no

trans. Therefore, DNA is the transforming factor

Hershey and Chase - bacteria, viruses, radioactive P & S - observed which material was injected (DNA) - Genetic material = DNA

Structure

DNA = deoxyribonucleic acid Made of repeating nucleotides (subunit) Nucleotide = sugar (deoxyribose), phosphate,

base 4 bases – adenine, guanine, cytosine,

thymine A & G = larger purines C & T = smaller pyrimidines

Chargaff (1949) – studies A always same % as T C always same % as G - so, _______________ = Chargaff’s Rules

Franklin – (1952) – X-ray diffraction - showed DNA as a tightly coiled spring =

helix Watson & Crick (1953) – used Franklin’s and

Chargaff’s info to determine structure Double helix held together by weak Hydrogen

bonds

DNA Replication

DNA separates into 2 strands – each serving as template for new strands

Point at which DNA splits = Replication Fork Enzyme (helicase) breaks H bonds and

untwists DNA Enzyme (DNA Polymerase) moves

complementary nucleotides in place to bond properly

Chapter 13 - RNA

RNA = ribonucleic acid 3 structural differences b/t DNA & RNA

DNA RNASugar = deoxyribose Sugar = riboseBase = thymine Base = uracilDouble helix Single stranded

Gene Expression

Step 1 = Transcription = DNA acts as template to make RNA Enzyme - RNA polymerase - reads DNA, binds at promoter - separates DNA strands - reads one side of DNA (template strand) - adds complementary RNA nucleotides

Transcription

So, transcription from DNA to RNA: template of DNA: A C G T A T G A T RNA:

Where? Because?

Genetic Code

= relationship b/t nucleotides in DNA & amino acids

Every 3 base letters of mRNA stands for an amino acid = codon

START codon = AUG STOP codons = UAA, UAG, UGA

Codon Table #2

Translation

Molecular Biology Dogma

DNA RNA Protein

Mutations

= heritable changes in a gene; lead to evolution

Can be : - neutral - harmful – ex. Cancer, sickle cell - helpful – resistance to poisons, HIV

Gene Mutations

Chromosomal Mutations

Chapter 14

Pairs 1-22 = autosomal chromosomes (autosomes)

23rd pair = sex chromosomes (determine gender)

- Male (XY); Female (XX)

Pedigree

Chart that shows inheritance of a trait over several generations

INHERITANCE PATTERNS

Complete Dominance Codominance Incomplete dominance Multiple Alleles Polygenic Environmental Conditions X-linked traits Sex influenced traits

MULTIPLE ALLELES TRAIT

= trait controlled by genes that have more than 2 alleles

- Any combo of 2 alleles produces different phenotypes

- Ex. Blood types

Genotype Phenotype

IAIA or IAIi Type A

IBIB or IBIi Type B

IAIB Type AB

IiIi Type O

Darwin - Evolution = genetic change in a species

over time Natural Selection = the process by which

organisms with variations most suited to their local environment survive and leave more offspring.

Ch 16 - Evolution

1 The Struggle for Existence Organisms produce moreoffspring than can survive. Grasshoppers can lay over200 eggs at a time. Only a small fraction of these offspring survive to reproduce.

2 Variation and Adaptation There is variation in nature,and certain heritable variations—called adaptations—increase an individual’s chance of surviving andreproducing. In this population of grasshoppers, heritable variation includes yellow and green body color. Green coloration is an adaptation: Green grasshoppers blendinto their environment and so are less visible to predators.

3 Survival of the Fittest Because their green colorserves to camouflage them from predators, green grasshoppers have a higher fitness than yellow grasshoppers. This means that green grasshoppers survive and reproduce more often than do yellow grasshoppers in this environment.

4 Natural Selection Green grasshoppers become morecommon than yellow grasshoppers in this population over time because: (1) more grasshoppers are born than can survive, (2) individuals vary in color and color is a heritable trait, and (3) green individuals have a higher fitness in their current environment.

Lamarck – - similar species descended from a common

ancestor - to explain changes, said acquired traits

were passed on to offspring Acquired traits = traits that arose during

lifetime, not determined by genes

Artificial selection = process in which nature provides the

variations, and humans select those they find useful.

Fossils Homologous structures = Structures shared by related species and

that come from a common ancestor

Evidence for Evolution

Analogous structures = Body parts that share common function, but

not structure ex. Bird wing and bee wing Vestigial structures = inherited from ancestors but has none or little

function Embryological development - similar in vertebrates

Genetics - DNA sequences shows organism’s history - closely related organisms will have similar

DNA sequences & similar amino acid sequences

All living things follow same genetic code

Ch 18 Classification

Systematics = science of naming and grouping organisms

Aristotle – B.C. – 1st to group living things - 2 kingdoms – Plant or Animal

Carolus Linnaeus – 1730s – Swedish botanist Binomial nomenclature – 2 part scientific

name Scientific name = Genus species or Genus

species Ex. Homo sapien or H. sapien

Ex. Carnegiea gigantia giant Segauro cactus Ex. Permyscus californicus common California mouse Ex. Nymphea odorata fragrant water lily Name – location, characteristics, scientist

Developed hierarchy : - Kingdom – broadest - Phylum - Class - Order - Family - Genus - Species – most specific

Cladogram – diagram that links organisms by showing how evolutionary lines branched off from common ancestors

Based on a derived character = trait that arose in the most recent common ancestor and was passed on

Six Kingdoms

Animalia Plantae Fungi Protista Archaebacteria Eubacteria

Three Domains

Domain – based on rRNA sequences 3 Domains - Archae (K. Archaebacteria) - Bacteria (K. Eubacteria) - Eukarya (K. A, P, F, P)

Ch 20 – Prokaryotes & VirusesBacteria Domain Archae - Kingdom Archaebacteria - walls lack peptidoglycan - DNA more similar to eukaryotes - live in extreme environments

Domain Bacteria - Kingdom Eubacteria - walls with peptidoglycan - larger domain - found everywhere

Eubacteria - grouped by 2 things 1. shape: - bacillus – rod - coccus – spherical - spirallus – spiral, corkscrew

2. Response to Gram Stain: - Gram positive – purple, retains stain; thicker

layer of peptidoglycan - Gram negative – pink, doesn’t retain stain;

thinner layer of peptidoglycan; unaffected by many antibiotics

Viruses

Size - ~20nm – 250nm Some char. of life, not all: - no nucleus, cytoplasm, organelles, or

membrane - no cellular functions - need a host cell to reproduce

Structure

Made of : 1. Nucleic Acid (DNA or RNA) 2. Protein coat around it (capsid) Some also have: - lipid envelope outside capsid *helps it infect cell - glycoprotein – used to attach to host cell

Viral Replication