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Understand the 5 characteris1cs of living things
Know what an adaptationis and what effects adaptations have on survival and reproduction
Know the steps of the scientific method, from observationsto conclusions
· Hypothesis:tentative, often narrow explanation regarding the natural. Must be testable and falsifiable.
· Theory:a well substantiated explanation of some aspect of the natural world. A unifying explanation of ideas by which are most certain.
· Atoms bond through chemical bonds: forces of attraction that hold atoms together
-first energy shell has room for 2 electrons
-the next two energy shells have room for 8 electrons each.
-If the outer energy shell is full, the atom is stable and will not react, if not they will gain or share electrons.
the sharing bond, satisfy the octet rule, some atoms will shareelectrons, shared e- travels around both nuclei
the stealing bond, if the difference in electro negativity is great enough, one atom willtake an e- from another.
ex: Naand Cl
o When the temperature drops, water molecules slowdown and keep their H bonds longer
o Locks into a crystalline lattice with its neighbors.
o Less molecules in a given space; the density isnow lower.
o There is a lowerdensity of water molecules in ice.
o 2. Lipids
o 4.Nucleic acids
difference between simple and complex carbohydrates, and howliving things use carbohydrates
Saturated fats contain all theH’s possible
· Singlebonds connect all carbons
· Solid atroom temperature
· Tend to be animal derived
Unsaturated fats have >1double bond b/t C’s
· Doublebonds produce kinks in chain
· Liquid atroom temperature
· Come from plants
isthe artificial addition of hydrogen atoms to an unsaturated fat. This canimprove a food’s taste, texture, and shelf-life.
· Not good for our health.
o If the shape of the protein is modified enoughto destroy its function, it is denatured.
Acidity can denature proteins
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
Each nucleotide consists of:
- 5-C sugar
Deoxyribos–the 5 carbon sugar in DNA
Different 5 carbon sugar- Ribos
- A phosphate group
- A nitrogenous base.
· Prokaryotes:simple structure, small.
o They have no membrane bound organelles
o They have no nucleus
· Eukaryotes:complex structure, larger
o Have membrane bound organelles
o Have membrane bound nucleus.
o Pigments are molecular bridges between sunlightand photosynthesis
o Plants are absorbing lights of differentwavelengths
o Wavelengths that are not absorbed are reflected(ie. Green)
Chlorophyll breaks down in the fall because the trees cannot create enough ATP to make more so then what is left is the carotenoids and they reflect reds/yellows/oranges and absorb all the other colors.
o Cellular Respiration
§ Aerobic=involvement of oxygen
· One of the most important properties of DNA isthe fact that it can be copied
· Stored information in a cell can be passed from
o Cell to cell
o Generation to generation
When balance between cell division and celldeath is lost,
Meiosis generates enormous variation
· Chromosome pairs align randomly and separateindependently
· 2^23 (8,388,608) combinations are possible
· 8 million + egg cells
· 8 million + sperm cells
· yielding more than 70 trillion genetically unique offspring
Purpose of sexual reproduction
· Variation in genetic makeup of a population
o Naturalselection acts on this variation
sequence of DNA that codes for a protein and thus determines a trait
o When all genes are turned on it is called totipotent (all powerful)
why is it significant that the genetic code is nearly universal among all organisms?
o Theory of Blended Inheritance
- Many thought that an offspring’s traits were blended from each parent
§ Easyto grow
§ Canbe cross pollinated by hand
-This allows the scientist to control the crossing (mating) of the plants
§ Hadeasily observable traits
why each somatic cell has 2 alleles per gene
· During meiosis, only on copy of each gene isplaced in each gamete
· A diploid cell can only have two alleles / gene
- one from each parent.
Mendel’s system of crossing plants
o Parental generation : P generation
o P’s offspring: F1 generation
o F1’s offspring: F2 generation
o And so on
· Started with a P generation that was TT or tt(true breeding)
· Crossed TT with tt , F1 generation was all tall
Sex‐linked traits refer to those traits that are more often expressed by male
· is any change in a cells DNA sequence
· Can be caused by errors in replication, or byenvironmental factors
EX: UV light, radiation, certain chemicals, viruses,etc.
· Mutations can affect the structure of the proteinthe gene is coding for.
o May render the protein dysfunctional
· Mutations are the raw material for evolution
o They create new versions of genes
Abase pair substitution – 1 base pair is substituted for another.
§ When there has been a base that was inserted into the sequence. The rest of the DNA sequence is shifted and the rest of the sequence after the insertion.
§ More profound affect on the structure of the protein.
§ Effects the RNA then structure of the protein.
§ When a base pair is deleted
§ The DNA sequence shifts to the left
§ Everything after the deletion is changed
§ More profound effect on the structure of the protein
o Theses are of tremendous biological importance,
§ Mutations can be passed to the next generation
o Mutation creates a new gene in a population
DNA and complexity
o No relationship between size of genome and complexity
o In humans, genes make up ~ 2% of DNA
§ Most DNA does not code for proteins.
o Massive collaboration (440 scientists; 32 labs)
- 15trillion bytes of raw data, 300 years of computer time.
o Human Genome project ‘was like getting a pictureof earth from space’
o At least 80% is both active and necessary
o At least 4 million gene switches
o Cystic fibrosis
o Sickle cell
o Huntington’s disease
o Down’s syndrome
o Kinefelter syndrome
o Breast cancer
Human Gene Therapy
The process of treating genetic disease byreplacing a mutated gene with a working gene in an individual’s cells
o Lipid cluster or genetically engineered virus.
· Single, chance mutation causes a defective toxicprotein
· Causes premature ageing in children
· Children usually die of a heart attack or strokebetween 7-20 years old
· New drug is showing promising results.
· All of the cells making up that face aregenetically identical
o Differentiated cells
o Differences in cells are not due to differencesin DNA, but rather the expression of that DNA
· Epigenteticsmeans above the genome
· Can switch genes on or off, affecting proteintranscription
· Aging causes epigenetic change in cells
· Repeated sun exposure causes skin to look olderbecause of excess cell division
drinking and smoking can effect your epigenetics and can pass on to generations.
· The genetic change in a population overtime.
o Population-group of individuals of the same species interacting.
o Change inallele frequency over time.
** Evolution is not a theory centered around the Origin of life on Earth.
evolution by natural selection
o Differential survival and reproduction amongindividuals of a population whose traits vary
o Mechanismof evolution
3 Conditions for Natural Selection
1. Variation for a trait
2. Variation must be heritable
3. Differential Reproductive Success
o more offspring being produced than can survive.
o Competition for resources
o Some individuals are better competitors, surviveand reproduce.
Variations in Traits
· Variations in traits influence and individuals ability to secure resources
o Influence survival and reproduction
Results of Evolution by Natural Selection
why natural selection doesn’t produce “perfect” organisms?
· in each generation, the alleles that code fortraits with better fitness tend to increase in frequency
o “good enough” individuals survive
· If the environment changes, which alleles arefavored may also change
o Traits may no longer be adaptive
Three modes of natural selection
o Intermediate phenotype
§ Stabilizing selection
o One extreme phenotype
§ Directional selection
o Both extremes phenotypes
§ Disruptive selection
1. Sponges- do not possess tissue or organs
2. Cnidarians- radially symmetrical
4. Annelids 3-7: 1st opening to form in
5. Molluscs development becomes animal’s anus
6. Roundworms 6 & 7: grow by molting
8. EchinodermsDeuterostomes9. Chordates
execretions/secretions, internal body fluids, MOST WIDESPREAD FORM OF DEFENSE
E.g. Octopus, milk weed, poison dart frog
-Energy flows through the ecosystem eventualy dissipated as waste head
-Elements can be recycled indefinitely between biotic and abiotic pools
-Nutrients= ~20 essential elements
the gut develops from front to back
Flower part just inside the sepals; often conspicuously colored to attract pollinators.
1. Bacillus: rod-shaped
2. Coccus: bead-shaped
3. Spirillum: squigly, spiral