BIO140-501 Exam 1, Chapters 1-3

Biology

the study of life

Hypothesis

an informed, logical, and plausible explanation for observations of the natural world

dependent variable

responds to changes in the independent variable, the “effect”

independent variable

the variable(s) that is manipulated by the researcher, the “cause”

Ex: The amount of water given to a plant. Independent or dependent variable?

independent

Ex: The size of the plant. Independent or dependent variable?

dependent

Controlled group

the group that is maintained under a standard set of conditions, with no changes in the independent variable

Experiment/treatment group

the group that is maintained under the same standard set of conditions, but the independent variable is manipulated

Step 1 of Scientific Method

Observation

What comes after Observation?

Research

What comes after Research?

Form a Hypothesis

What comes after Hypothesis?

Predictions

What comes after Predictions?

Design and conduct an Experiment

What comes after Experiment?

Analyze the data

What comes after Analysis?

Draw a conclusion

What comes after Conclusions?

Share results

Last step of Scientific Method

Communicate any questions and modify if needed

What is the difference between data supporting a hypothesis and a hypothesis being proven?

Hypotheses can be supported, but no amount of testing can prove a hypothesis with complete certainty

scientific theory

a hypothesis that has been tested and received substantial confirmation through independent researchers; a general statement

primary literature

the first publication of scientific research that contains actual data with controls

ex: primary literature

peer-reviewed science journals

secondary literature

provides basic overview of the topic or summarizes research

ex: secondary literature

textbooks, review articles, reputable news outlets

What makes a source reputable?

CRAAP: currency (when was it published?), relevance (does it fit for your needs?), authority (who created it? Credentials), accuracy (is the information correct?), purpose (why was it created? Does it lack bias?)

Peer review

a study reviewed by scientists who did not participate in the experiment and bring up any concerns or questions that will be answered by the author

Correlation

two or more aspects of the natural world behave in an interrelated manner; if one aspect shows a particular value, we can predict a value for the other aspects

causation

a statistical relation indicating that a change in one aspect of the natural world causes a change in another aspect

Confronting pseudoscience

correlation does not prove causation

Atom

the smallest unit of element that retains the element’s properties

Element

a type of matter, a pure substance with distinct physical and chemical properties, cannot be broken down by ordinary chemical methods

Proton

inside the nucleus, has a positive charge

Neutron

inside the nucleus, has no charge

Electron

surrounds the nucleus by its shells, has a negative charge

Ion

atoms that have lost or gained electrons and become either positively or negatively charged

Isotope

a form(s) of an element that has a the same number of protons but different number of neutrons

How are isotopes used in science and medicine?

diagnosing and treating diseases, medical imaging, C-dating, biological tracing

Atomic number

number of protons in an atom’s nucleus

Where can the atomic number be found?

top left

Mass number

the sum of protons and neutrons of an isotope

Where can the mass number be found?

bottom left

How does an atom achieve a positive charge or a negative charge?

when it gains or loses electrons and becomes an ion

Why are ions important in science and medicine?

muscle movement, nerve impulses, and fluid levels in the body

Ionic bond

weak, the attraction between a negatively charged ion and a positively charged ion, the transfer (gain/lose) of the valence electrons between the atoms

Nonpolar covalent bond

strongest, sharing of electrons between two atoms; the electrons are shared equally

Polar covalent bond

strongest, sharing of electrons between two atoms; the electrons are not shared equally and are being pulled to one pole

hydrogen bond

weakest, a slightly positive hydrogen atom that is attracted to the negative atom (O, N, F)

Evaporative cooling

a process that cools air by evaporating water

Which types of chemical bonds are strong?

Covalent, ionic, and metallic

Which types of chemical bonds are temporary?

Hydrogen bonds

Solvent

the fluid part; dissolving agent

Ex: solvent

coffee, water

Solute

substance that is dissolved

Ex: solute

sugar, salt, lemonade mix

Solution

any combination of a solute and a solvent

Soluble

a compound that mixes completely with water

Why is water an excellent solvent?

it is attracted to the -/+ charges, which pulls solutes apart

What types of bonds does water attract?

ionic and polar bonds

Adhesion

the attraction between molecules of different substances

Cohesion

the attraction between molecules of the same substance

pH

measures how acidic or basic a substance is by its concentration of hydrogen ions

0 ph

highest concentration or very acidic

7 ph

equal concentration or neutral

14 ph

lowest concentration or very alkaline

Hydrophobic

water-fearing, not soluble in water, nonpolar covalent bonds

Ex: hydrophobic substance

oil

Hydrophilic

water-loving, soluble in water, ionic and polar covalent bonds

Ex: hydrophilic substance

sugar, salt

What elements do all the major biomolecules have in common?

carbon, hydrogen, and oxygen

Building blocks of carbohydrates

monosaccharides; simple sugars

ex: monosaccharides

glucose, fructose

ex: disaccharides

sucrose (glucose + fructose), lactose

ex: polysaccharides

starch, cellulose, glycogen

glycogen

energy storage for animals

cellulose

the main structural component in plant cell walls

starch

energy storage for plants

sucrose

another energy source and energy transport for plants

lactose

another energy source, aids calcium absorption

glucose

primary source of energy

fructose

energy source as a fast-absorbing sugar

Building blocks of nucleic acids

nucleotides

Components of nucleotides

five-carbon sugar, phosphate group, and a nitrogenous base

DNA

DeoxyriboNucleic Acid, built with two strands of joined nucleotides; provides a long-term, stable genetic information; the “blueprint”

RNA

RiboNucleic Acid, built with one strand of nucleotides; temporary, the messenger that interprets, transfers, and executes instructions

Building blocks of proteins

amino acids, has four levels of structures

Protein functions

maintain chemical reactions, structural support for cell shape, transmit signals, flags invaders in cells

Ex: proteins

insulin, antibodies, hemoglobin

How are all lipids related?

their inability to dissolve in water; are not built with polymers, composed of hydrocarbons

What is unique about a phospholipid molecule?

crucial, being the main component of all cellular membranes; amphiphilic characteristic, hydrophilic phosphate head and two hydrophobic fatty acid tails •==•

Saturated fat

hydrogen carbon chains connected by single bonds; solid at room temperature

Unsaturated fat

hydrogen carbon chains with one or more double bonds that create kinks; liquid at room temperature

Steroid

a chemical compound, based on four rings of carbon, mimicking hormones; type of lipid

What type of biomolecule is an enzyme?

proteins; biological catalysts to speed up chemical reactions

What bond makes up water?

polar covalent bonds

Water is a ____ solvent?

universal

Cohesion of water molecules

attraction of water molecules for other water molecules

Ex: Cohesion of water molecules

water droplets sticking together

Adhesion of water molecules

attraction of water molecules and other substances

Ex: Adhesion of water molecules

water droplets sticking to glass

Evaporative cooling of water

water cools the surface, it evaporates from