bio

LOOK AT OBJECTIVES

biology = study of life

the seven traits that define living organisms

A. characteristics of living organisms

  1. have organization: atoms = molecules - organelles - cells - tissues - organs - organ systems (not all organisms have all of these things)

  2. acquire and use energy

  3. maintain constant internal conditions (homeostasis)

  4. have inherited information (DNA) that determines form and function

    1. DNA has the instructions on how to make protein

  5. all these organisms are composed of 1 or more cells

  6. all organisms will respond to their environment (ex. walking outside when it’s hot makes you sweat. when it’s cold, you shiver)

  7. all organisms reproduce

humans (the big six):

things we need (on a consistent basis) to survive: sleep, nutrition, exercise, socialization, learning, time outside

B. Science = collection of unified insights about nature, the evidence for which is an array of facts

  1. facts are explanations thought to be true

  2. science does not deal with absolute truths

  3. list of scientific sources best to worst:

    1. peer reviewed journals

    2. reviewed texts (textbook)

    3. science books

    4. science magazines (like national geographic)

    5. newspapers/TV

    6. web/social media

  4. theory = generalization that explains many observations - has been tested and researchers have yet to find evidence that disproves it - usually generates many hypotheses

  5. hypothesis = tentative, testable explanation for observed phenomenon

C. Scientific method (describe it and be able to apply it to a given problem):

  1. steps of ^

    1. observation

    2. hypothesis (never say it’s true cause you can’t ever prove anything is absolutely true)

    3. experiment/test

    4. conclusion

  2. independent variable, dependent variable, and control samples

    1. independent variable - factor of the experiment being tested (whatever is being changed or made different)

    2. dependent variable - (what we use to measure the change, for ex. measuring the heart rate, which is the DV) response or change that occurs due to the IV

    3. control sample - a sample where a the IVs are omitted

chapter 2 - chemical basis of life

A. element - a substance that can’t be reduced to a simpler substance (composed of atoms)

B. atom - basic unit of matter composed of protons, neutrons, and electrons

  1. nucleus = very little space, but contains nearly all the mass of the atom

    1. protons (+ charge, inside the nucleus) determine the atomic # of an element

      1. ex. hydrogen - atomic # of 1, 1 proton - the number of protons never changes, therefor the atomic number is always equal to the number of protons

    2. neutrons - (in nucleus) have no charge

      1. isotopes - are just atoms of the same element with different weights because they have a diff number of neutrons but same number of protons.

        1. ex. carbon (atomic # of 6) ~ C12 = 6 protons + 6 neutrons

        2. 12 is the mass number - it’s the protons + the neutrons

        3. C14 is radioactive which means it’s a radio isotope - an isotope that has an unstable nucleus - loss of particles from the nucleus

        4. ability to form four covalent bonds so it can bond with all types of things

    3. electrons (surround the nucleus), ions and electron shells

      1. electrons (- charge) have very little mass

      2. ions - atoms that differ in the # of protons and electrons = pos or neg (more protons than electrons, will be pos. more electrons than protons, will be neg.)

      3. electrons are found in shells, and each atom attempts to fill its outer shell

        1. two electrons fill up the first shell

        2. every shell after the first is full with eight electrons

        3. atoms will form bonds to satisfy the requirements of their outer shell (they want to have a full outer shell, whether that means losing electrons to go back to a full shell or gaining electrons)

      4. a neutral atom has an equal number of protons and electrons

C. Molecule - when two or more atoms join together to form something new. (they are bound together and they want to fill their outer shells)

  1. covalent bonds - bonds in which atoms share electrons

    1. polar covalent bonds - shared electrons spend more time near the larger nucleus - the charge is on 1 end of the molecule

    2. hydrogen is the biggest weakling and it will be pulled anywhere

    3. hydrogen will be the positive end because all of its electrons are being pulled away from it

      1. ex. h2o

    4. hydrogen bonds - formed when partially positive hydrogen atom in a polar covalent bond is attracted to a partially neg. atom in another polar covalent bond - opposites attract - ex. water and ammonia

    5. ionic bond - atoms bonded through attraction of oppositely charged particles (ions) - exchange electrons

D. solutions, solutes, solvents

  1. solution - mixture of 2 or more substances (ex. solute dissolved in a solvent)

  2. solute - substance that is dissolved in a solvent

  3. solvent - the substance in which a solute is dissolved

    1. sugar water - the solution

      1. sugar is the solute

      2. water is the solvent

E. water - provides the basis for life

  1. freezes at 0 degrees celsius (32 degrees F) - ice = less dense dense than water - molecules spread apart

  2. water has high specific heat

  3. buffers climates - areas that are close to big bodies of water change temp more quickly(?)

    1. june 21, dec 21 solecists

  4. surface tension - water molecules bond together more strongly than water molecules to air

  5. hydrophilic molecules - interact with water - anything that dissolved in water is a hydrophilic molecule - ex. salt

  6. hydrophobic molecule - doesn’t interact with water - ex. oil

F. acids and bases

the pH of our blood is about 7.4

  1. acids - lower pH

  2. bases - raise pH

    1. alkaline is a synonym for basic

  3. measuring acidity or alkalinity

    1. pH scale is from 0 - 14

    2. 0 = most acidic

      1. more hydrogen ions (H^+)

    3. 14 = most basic

      1. more hydroxide ions (OH^-)

      2. raise pH and makes things neutral

    4. 7 = neutral

  4. living organisms usually thrive in a pH of 6-8

    1. some parts of organisms are very acidic - ex. stomach

  5. when the pH in your body is too low it’s called acidosis

  6. when the pH in your body is too high it’s called alkalosis

  7. your bodily pH is very important - must stay close to neutral

G. Organic Compounds - always contain carbon

  • carbon has two electrons in its inner shell and four electrons in its outer shell

  • hydrocarbons - chain of carbons and hydrogens

    1. ex. propane

  1. functional groups - the groups of atoms in an organic molecule - where chemical reactions take place

    1. FG - hydroxyl, carbonyl, carboxyl, amino, phosphate (know what molecules they are found in and how to draw)

H. Most organic molecules are repeated units

  1. monomers - single units

  2. polymers - string of monomers

I. Carbohydrates

  1. contain C, H, O

  2. monosaccharide (type of monomer):

    1. C6H12O6 - Glucose

      1. other ex. fructose, deoxyribose

  3. Polysaccharide (polymer) - many monosaccharides linked together

    1. starch - carbohydrate storage in plants

    2. glycogen - how animals store carbohydrates

      1. excess glucose that’s in bloodstream converts to glycogen and vise versa

    3. cellulose - primary structural component of plants (provides rigidity). Animals can’t digest, only bacteria can

      1. humans can’t digest cellulose so we don’t get any energy from it

      2. cellulose increases how fast things move through your digestive system

    4. chitin - (second structural polysaccaride) strengthens the exoskeleton of many organisms

      1. ex. insects and arthropods

J. dehydration (cause giving off water in the process) synthesis —> when molecules bond to one another & produce H2O

ex. glucose + glucose = maltose

K. hydrolysis —> when a more complex molecules is split into simpler molecules and water is required

ex. maltose is broken down into two glucose molecules

L. lipids - oils, fats, steroids

  1. characteristics of lipids

    1. composed of C, H, O - more H

    2. used for energy storage and insulation

    3. hydrophobic

  2. fat (type of lipid) - glycerol + fatty acids

    1. fatty acids = a carboxyl and a long hydrocarbon chain

    2. saturated fat vs unsaturated fat: single bonds vs double bonds from carbon to carbon

      1. double bonds = unsaturated

      2. single bonds = saturated

  3. steroids (type of lipid): all have a set of 4 linked carbon rings

    1. try to be able to identify a molecule by looking at

    2. side chains are different

    3. cholesterol is a steroid

    4. ex. testosterone - every point of the hexagons have a carbon attached

  4. phospholipids - make up the outer membrane of the cell

    1. the cell membrane allows certain things to go in and out of the cell

      1. 2 fatty acids and a phosphate group

      2. fatty acid tails are hydrophobic, but phosphate heads are hydrophilic

M. Protein - polymer made up of many amino acids (which are monomers)

  1. all amino acids have an amino group and a carboxyl group attached to a central carbon

    1. proteins consists of polypeptide chains made up of amino acids

    2. protein functions are numerous and depend on the protein’s shape

  2. monosaccharides make up the polysaccharides

  3. amino acids are the monomers that make up protein, which are the polymers

    1. nails and hair are made out of proteins like keratin

  4. change in the environment can change the shape of a protein = denature the protein

    1. ex. frying an egg

  5. lipoproteins - capsule of protein that surrounds a globule of lipid

    1. important for transporting lipids in and out of the bloodstream

    2. LDL = low density lipoprotein - carry cholesterol to coronary arteries of the heart

      1. really want this number to be low, less than 100

    3. HDL = high density lipoprotein - cleans the cholesterol off your arteries and to your liver

      1. want this number to be high, more than 40 for guys and more than 60 for girls

    4. Apo’B - needs to be less than 90 - tested for people who have a family history of heart disease

N. Nucleic Acids - DNA and RNA is what we’ll talk about most

  1. deoxyribonucleic acids (DNA) contains the instructions to make proteins

  2. ribonucleic acid (RNA) takes DNA encoded instructions to the sites in cells where protein

    1. DNA and RNA are composed of nucleotides

    2. nucleotides are composed of a phosphate group, a 5 carbon sugar, and a nitrogen containing base (Guanine, Cytosine, Thymine, and Adenine)

    3. half of DNA comes from mom, the other half is your dad

Chapter 3: Cells

A. Prokaryotes vs Eukaryotes

Prokaryotes:

  • archaea or bacteria

  • no nuclei

  • single celled

  • many do not use oxygen

  • no organelles

Eukaryotes:

  • everything else

  • nuclei

  • many are multicellular

  • most use oxygen

  • organelles

B. Eukaryotic Cell

  • nucleus - membrane bound department - contains DNA

  • plasma membrane - outer boundary of the cell

  • cytoplasm - region in side the plasma membrane but outside the nucleus (it’s everything in the cell but the nucleus)

  • organelles - structures within the cell which carry out specific functions

  • nucleolus - within nucleus - contains RNA & proteins - they combine to make ribosomal subunits - will make up ribosome

  • ribosome - structure that translates RNA to proteins

  • cytoskeleton - internal scaffolding that maintains the shape of the cell

  • cytosol - fluid in in the cytoplasm

  • rough endoplasmic reticulum (in cytoplasm) - network of plasma membranes that has ribosomes embedded in the surface

  • smooth ER - detoxifies potentially harmful substances and makes lipids

  • golgi complex - distribution center for proteins - tale proteins in, modifies them, and then ships them out to their final destination

  • vesicle - tiny membranous sacs in the cytoplasm

    • important vesicle: lysosome - organelles that contain enzymes that break down organelles and return them to the cytosol so they can be reused - also digest nutrients

    • peroxisomes - vesicles containing enzymes which break down fatty acids and amino acids

  • mitochondria - converts food energy into ATP - ATP is essential to our life

  • cytoskeleton

    • microfilaments - changes in cell shapes (actin, myosin)

    • intermediate filaments - skeleton

    • microtubules - move organelles from one area to another also cell extensions - cilia and flagella (which eat and destroy bacteria)

  • plant cells

    • central vacuole

      • may contain 90% of the cell volume

      • contains mostly water, but also nutrients and waste

  • cell wall - our cells just have cell membranes, not cell walls

    • located outside the cell membrane

    • cell walls are found in plants, bacteria, algae, and fungi

    • made of cellulose (polysaccharide)

  • plastids

    • chloroplasts - where photosynthesis takes place