Biology Review

Units 7 - 15

ASEXUAL VS SEXUAL REPRODUCTIONASEXUAL REPRODUCTION

SEXUAL REPRODUCTION

Creates identical copies (clones)Only involves MITOSISONE parent involvedCommon in bacteria and unicellular protists

Adds genetic variationInvolves meiosis and fertilizationTWO parents involvedDiploid and haploid cells

MITOSIS AND MEIOSISMITOSIS

MEIOSIS

One division2n → 2n

(same number of chromosomes)

Results in 2 genetically identical cells

Two divisions2n → n

Half the number of chromosomes

Results in 4 DIFFERENT haploid cellsForms gametes (egg and sperm)

DNA DNA is a polymer of nucleotides.

A nucleotide is made up of three parts: a sugar, a phosphate and one of four basesIn DNA, the bases are A, T, C, and G

DNA’s shape is a double helixThe two strands are held together by HYDROGEN bondsA binds to TC binds with G

DNA REPLICATION Process of DNA copying itself Steps

DNA Unzips (Hydrogen bonds break)Each side acts as a templateNew DNA nucleotides are added according to base-pairing rulesTwo new molecules of DNA result – each with one old and one new

strand. Happens in INTERPHASE (before mitosis or meiosis)

PROTEIN SYNTHESIS Remember, genes are made of DNA and are in the nucleus Genes (DNA) contain the instruction for making  a protein In transcription, DNA is used to make mRNA in the nucleus mRNA then leaves the nucleus and goes to the ribosome In translation, tRNA then brings amino acids in the proper order to make the

protein on the ribosome.

DNA → mRNA → protein

Made of amino acids

PROTEIN SYNTHESIS

CAN YOU IDENTIFY THE PARTS?1. DNA2. mRNA3. Nucleus4. Cytoplasm5. Ribosome6. Codon7. Anticodon8. tRNA9. Amino acid10.Protein

(polypeptide)

READING THE CODON CHART Be sure to use

mRNA You won’t have

to memorize this!

What amino acid is coded for by the DNA

ATA GAGFirst convert DNA to mRNAATA GAGUAU CUC

UAU = tyrCUC = Leu

GENETICS We have two genes for each trait

– this is our GENOTYPE One gene came from mom, one

from dad If the genes are alike, the

individual is homozygous (RR, rr)

If the genes are different , they are heterozygous (Rr)

Some genes are dominant and others are recessive

We only show a recessive trait if we have no dominant gene

RR and Rr would “look” dominant

rr would look recessive

This diagram shows the cross between 2 heterozygous purple flowers

Cross is: Bb x Bb Notice that 75% are purple and 25%

white

SEX LINKAGE Females are XX Males are XY Sex-linked traits

are on X chromosome

Trait is more common in MALES

Examples are colorblindness and hemophilia (blood fails to clot)

• Males give X chromosomes to their daughters and Y’s to their sons

• Moms give X’s to both daughters and sons

CODOMINANCE – BLOOD TYPE Four blood types▪A, B, AB, O

Three different alleles: A, B or neither

A = AA or AOB = BB or BOAB = ABO = OO

Agglutinogen = protein

PEDIGREESTracing traits through

generations Males are squares Females are circles Horizontal line means married Vertical line means children Filled in circle means the

individual HAS the condition Can you identify the

genotypes of individuals 4, 7, 12?

4 = Ee (parent 2 had to give an e)7 = Ee (child is ee, so they had to have one e)12 = ee (affected with recessive condition)

A chart s

howing

arrangement o

f

chromosomes

KARYOTYPE

In humans, 22 pair of autosomes1 pair of sex chromosomesXX = femaleXY = maleExtra chromosomes a result of

non-disjunctionChromosome pairs fail to separate in meiosisOne example is DOWN SYNDROME (extra 21)Another example is KLINEFELTERS (XXY)

XY = male

3 21’s = Down Syndrome

GENETIC TECHNOLOGY

TRANSGENIC ORGANISMS

DNA FINGERPRINTING

Organisms that have 2 different kinds of DNAGene cloningUses bacteria to make human proteins like insulin

Use gel electrophoresis to compare DNA fragmentsIF DNA matches, it’s from the same individual

Evidence points to suspect 2

EVOLUTION – CHANGE OVER TIMEEVIDENCE NATURAL SELECTION

Fossil evidenceFossils found in sedimentary rockLower level fossils are older and

more PRIMITIVEWe can compare fossils to modern

organismsSimilar structure suggests common

ancestorBiochemical evidence

DNA and protein similarities suggest common ancestor

Credited to Charles DarwinOrganisms in populations have

variations that can be passed from generation to generation

More organisms born that environment can support

Organisms compete for resourcesThose organisms with favorable

variations have more babies and the population evolves

CLADOGRAMS

DETERMINING EVOLUTIONARY RELATIONSHIPS

Which type of plant is most closely related to flowering plants?

CONIFERS

HISTORY OF CLASSIFICATION SYSTEMS

o Aristotle – Plants and Animals o Linneaus – developed BINOMIAL

NOMENCLATUREo TWO KINGDOMS: plants and animalso THREE kingdoms: plant, animal,

Protisto FIVE kingdoms: plant, animal,

Protist, fungi, Moneran

CLASSIFICATION

Scientific name is genus and species name. Organisms in same genus are closely related

FIVE KINGDOM CLASSIFICATION

DICHOTOMOUS KEY• Always begin with #1• Follow directions using choices given• What shape is “Gina”?• Equilateral triangle

TYPES OF PLANTS

PLANT ADAPTATIONSROOT, STEM, LEAF

FLOWERS AND FRUITSRoots are adapted to absorb water with root hairsLeaves are adapted for photosynthesis by being flat and greenStems move water with xylem

Flowers have bright petals to attract pollinatorsPollen (Sperm) can be transferred by animalsWhen egg joins with pollen, a seed is formed in the ovaryThe ovary becomes the fruitFruit surrounds and protects seedFruit also helps get baby plants in seeds away from parent plant

TYPES OF ANIMALS

DISEASE CAUSING VIRUSESVIRUS STRUCTURE

VIRAL REPRODUCTION

A virus is not made of cellsIt is nucleic acid (DNA or RNA) surrounded by protein coat (Capsid)

Virus can’t reproduce unless it is inside a living cellThe virus uses the cells enzymes and ribosomes to make DNA and proteinNew viruses either bud off of the cell or the cell bursts, releasing lots of viruses

BACTERIA VS VIRUSESBACTERIA VIRUS

Made of cellsCan be killed by antibioticsExamples of disease caused by bacteria is strep throat

Not made of cellsMUCH SMALLER THAN CELLSCan’t be killed by antibioticsExample of diseases caused by viruses are AIDS (HIV), Smallpox, Influenza

INTERNAL AND EXTERNAL FACTORS IN DISEASE

IMMUNITY

PASSIVE VS. ACTIVE IMMUNITYPASSIVE IMMUNITY

ACTIVE IMMUNITY

Person does NOT make memory cells or antibodiesAntibodies only are transferredDoesn’t provide long-term protectionNatural: from breastfeedingArtificial: Rabies “shot”

Person DOES make antibodies AND memory cellsProvides long term immunityNatural: you have diseaseArtificial – you get a VACCINATION

BEHAVIORAL ADAPTATIONS

BEHAVIOR IS ANY THING AN ANIMAL DOES. ANIMAL BEHAVIORS ALSO HELP ANIMALS

SURVIVE AND/OR REPRODUCE.

Innate Behavior

o Innate behavior is also called inborn behavior.

o It is programmed in DNAo Innate behaviors include

reflexes and instinctso Exampleso human suckling.o spiders spinning webso Migration: birds flying south for

the wintero Hibernation – dormant when

coldo Estivation – dormant when hot

LEARNED BEHAVIOR

SOCIAL BEHAVIOR

CARBON CYCLE Cycling of carbon and oxygen Three main processes

Photosynthesis – plants use carbon dioxide; produce oxygenRespiration – uses oxygen, produces carbon dioxide (both plants and animals)Combustion – burning – releases more carbon dioxide

Greenhouse Effect•Carbon dioxide traps heat in the atmosphere, making life possible•Increased carbon dioxide can make temperatures rise more•Human activities can lead to GLOBAL WARMING

BE A GOOD STEWARD