Bio 161 Exam #1

Scientific Process

1. Make observations

2. Formulate a question

3. Formulate a hypothesis

4. Devise one or more testable predictions

5. Conduct an experiment

6. Analyze data/draw conclusions

Hypothesis

-Has to be falsifiable

-Proposes an explanation for what is not yet known

-Proposed explanation for a natural phenomenon

Prediction

-Use if/then statement

-If (restate hypothesis)

-Then.. describe expected comparison between experimental and control groups

Manipulative or controlled

-One variable is manipulated by the experimenter then manipulated and control groups are compared

Natural or observational

-Naturally occurring variations are compared

-No variable changes

-Still needs a comparison group

Variable

-Factor that can by set by an experimenter to test its effect on a phenomenon

-Only one variable to distinguish experimental and control groups

Blind experiment

-Subjects of experiment do not know which treatment they receive

Double blind

-Neither the subjects nor the experimenter know which treatment in recieved

Quantitative analysis

-Of data, compares measurements between groups

Statistical Analysis

-Ask if differences are likely and not just do to chance

Theory

-Explanatory hypothesis that has been repeatedly well supported by empirical data

Ex. theory of evolution, cell theory (all living things made of cells)

Cell Theory

-Cells are the fundamental unit of life

-All organisms are composed of cells

-All cells come from pre-existing cells

Three Domains of Life

-Bacteria

-Archae

-Eukarya

Prokaryotes vs Eukaryotes

-Prokaryotes don’t have organelles (membrane bound structures in cytoplasm)

-DNA not within membrane bound nucleus

Nucleoid

-Region within cytoplasm of prokaryotic cell occupied by DNA

Plant Cell

-Chloroplasts

-Cell wall

-Large vacuole can fill with fluid and push against cell wall to give turgor pressure

Nucleus

-Contains genetic material, DNA

-DNA is assembled with proteins into chromosomes

-Nucleus has a double membrane (nuclear envelope)

-Nucleolus: compact DNA region within the nucleus with genes that code for ribosome components

Rough Endoplasmic Reticulum

-Ribosomes for protein synthesis are attached to the outside; proteins then enter the ER

-Within the ER, proteins are modified, folded and, prepared for transport

Smooth ER

-No ribosomes attached

-Function in lipid synthesis

Golgi

-Proteins travel from ER to golgi

-Stack of membrane bound structures where proteins are modified then sorted and prepared for transport

-Vesicles are small-membrane bound transport units

Vesicles containing proteins pinch off the ER, fuse to the golgi where proteins are modified, pinch off golgi and travel to locations inside the cell or fuse to plasma membrane and release contents

Lysosome

-Have enzymes to digest components

-Acidic inside, their enzymes

Phagocytosis “cell eating”

-White blood cells taking up a bacterium as part of immune response

Mitochondrion

-Have a double membrane and own DNA

-Both are evidence for endosymbiotic theory

Chloroplasts

-Have double membrane and own DNA, evidence for endosymbiotic theory (evolution from engulfed photosynthetic bacterium)

Endosymbiotic Theory

-An ancient, free-living prokaryotic cell was engulfed by another cell and they had a symbiotic relationship. Large cell provided protection, engulfed cell provided energy.
Evidence:

-Mitochondria and chloroplasts have their own DNA

-Divide by “pinching”

-Are surrounded by a double membrane

Element

-Chemical substance that cannot be broken down into other substances

Atom

-Smallest unit of matter holding properties of an element

-Cannot be further divided without releasing charged particles

Shells

-Energy levels around the nucleus

-Outermost is the valence shell

Electronegativity

-Tendency of an atom to attract electrons

Affected by

-Number of positive charges (protons) in nucleus

-Distance from the nucleus

Covalent Bonds

-Sharing of electrons

Nonpolar Covalent

-Equal sharing of electrons

-Occurs when 2 atoms have similar electronegativity

-No charges present

Polar Covalent

-Unequal sharing of electrons

-Occurs when 2 atoms differ in electronegativity

-Partial charges exist around the atoms within the molecule

Ionic Bonds

-Involve the transfer of electrons from one atom’s valence shell to another valence shell

-Ion: charged particle that forms when atoms gain or lose electrons

Hydrogen Bonds (noncovalent)

-H with a partial positive charge

-Another atom with a partial negative charge

-Represented with dots and dashes

Ex. two water molecules

Hydrophilic

-Substances that interact with water

Hydrophobic

-Molecules unable to interact with water

Hydrophobic Interactions

-Non-polar molecules will tend to associate with each other when in a polar solvent like water

London Dispersion Forces

-Interactions between nearby non-polar molecules, when a random slight “shift” in electron cloud causes slight partial charges that can then interact

-These are Van der Waal forces, which are weak and transient

Mole

-Unit to measure the number of particles of a particular substance

-Can refer to atoms or molecules

Molar Mass

-Refers to the weight of a mole of a particular substance

-Grams/mol

Molarity

-Describes the amount of solute molecules per volume of solution

-Moles of solute per liter of solution

Materialism

-Nature is composed of matter and energy, and behaves by discoverable, constant rules

Empiricism

-Relies on evidence obtained through observation and testing

Centrioles

-Help organize microtubules to help with cell division and movement

Microtubules

-Tiny, hollow tubes made of protein that help support cell shape, move materials inside cells, and separate chromosomes during cell division.

Valence Shell

-Outermost electron shell of an atom

-These electrons take part in chemical reactions and bonding

Solute

Solvent

-does the dissolving

Solute

-substance getting dissolved

Solution

-uniform mixture made by dissolving a solute in a solvent

Acid

-h + donor

Base

-h+ acceptor

Experimental vs control group

-receives the specific treatment

-control group does not receive any treatment, kept in normal conditions

-a good control group must use placebo and match experimental group in every way possible