Biology Exam 2 part 1

What are some characteristics of life?

What are some characteristics of life?

reproduction, movement, response to external stimuli. composed of cells, maintain homeostasis, metabolism

Homeostasis

Maintenance of a constant internal environment despite changes in external environment

Why are zombie not alive?

don't grow, respond to limited stimuli, limited homeostasis does not promote healing, eat but do not metabolize

Why are mules not "alive"?

can't reproduce, no evolution of populations,

What are the characteristic of a virus?

common set of biological molecules, reproduce by infecting cells of other organism, no metabolism, no homeostasis

Which substance is a molecule rather than an element?

carbon dioxide, made up of atoms combined together, one carbon two oxygen

Elements

fundamental forms of matter, composed of atoms that can not be broken down by normal means

Atom

smallest unit of an element

Protons

Positive Charge

Neutrons

Neutral=no charge

Electrons

negative charge

Neutral Atom

equal numbers of protons and neutrons

Ions

atoms with a difference in number of protons and electrons

Why is water able to dissolve substances so well?

waters polarity attracts other polar molecules

What type of chemical bond shown in this diagram causes different water molecules to be attracted to one another?

Hydrogen bonds

Water

is a molecule, a good solvent, facilitates chemical reactions, moderates temperature

Molecule

two or more atoms held together by chemical bonds

What makes up a water molecule?

2 hydrogen, 1 oxygen

Hydrogen Bonding

weak attraction between molecules, slight negative oxygen attracted to slightly positive hydrogen

Nonpolar molecules

electrons shared equally

Hydrophobic

water fearing, molecules don't dissolve in water

Solution:

a chemical mixture

Solute

a substance that dissolves in a solvent

Solvent

substance that dissolves solute

Are macromolecules hydrophobic or hydrophilic?

hydrophilic

What can water's polar structure not disolve?

nonpolar (hydrophobic) molecules

Chemical Reactions

changes in chemical composition of substances

Reactants

starting materials in a chemical reaction

Products

result of chemical reaction

Why can water can absorb a lot of heat?

hydrogen bonds are disrupted first, heat raises water temperature

Bad Science

alternate hypothesis not explored, scientific method not followed, bias not reduced/eliminated

Pseudoscience

information presented as science but does not hold up to scientific scrutiny

What's an example of Pseudoscience?

the bermuda triangle

What might be a cause for the "mysterious" ship/plane disapearences in the bermuda triangle?

bubbles reduce density of water, causing ships to sink, methane sets on fire from lightning, causing planes to go down

Organic Chemistry

chemistry pertaining to biology

Carbon Containing Molecules

carbon interacts with elements to produce complex molecules

Covalent Bonds

share electrons

single bonds

one pair of electrons

double bonds

two pairs of electrons

Ionic Bond

electrons transferred between atoms

How many bonds can carbon form?

four bonds

What category of macromolecules includes testosterone and estrogen?

Lipids

Macromolecules

large organic cells, found in living organisms

What can macromolecules be found in?

carbohydrates, proteins, lipids, nucleic acids

Carbohydrates formula and use

Carbon oxygen and hydrogen (CH2O), major source of energy for cells

What are carbohydrates made of?

sugar subunits

Proteins

required for a wide variety of processes, structural component of cells, muscles made of protein

Enzymes

proteins that accelerate chemical reactions that build and break molecules in cells

What is protein made of?

amino acid

what are Amino Acids made of?

carbon, hydrogen, oxygen, and nitrogen

Peptide

short amino acid chain

Polypeptide

long amino acid chain

Protein

one or more polypeptide (usually >50 amino acids)

What do different amino acid combinations equal?

different shapes and properties for proteins

Lipid

comprised mostly of hydrocarbons, partially or entirely hydrophobic

What are the three types of lipids?

fats, steroids, phospholipids

Fats

3 carbon skeleton and 3 fatty acid tails

Steriods

4 fused carbon rings, ex. cholesterol, sex horomones

Phospholipids

3 carbon skeleton and 2 fatty acid tails and a phosphate head group

What is special about phospholipids?

hydrophilic head and hydrophobic tail

Nucleic Acids

made of nucleotide monomer subunits

Nucleotide

sugar+phosphate+nitrogenous base

RNA

ribonucleic acid, ribose sugar, single stranded, helps cells make proteins

DNA

deoxyribonucleic acid, stores genetic info, deoxyribose sugar, rungs of nitrogen base pairs

What are the four complementary nitrogen bases?

adenine, guanine, thymine, cytosine

Bases form hydrogens with a complimentary base?

A bonds with T G bonds with C

True or False: Scientific evidence shows that the animo acid tryptophan in turk is what makes you drowsy on thanksgiving.

false

Theory of evolution

explains how a singular ancestor 4 billion years ago gave rise to all life

All living things are made up of what?

cells

Prokaryotes

Bacteria, small, microscopic, genetic material not in a nucleus, no organelles, cell walls (outside cell membrane)

Eukaryotic

Larger, complex, genetic material in nucleus, membrane-bound organelles, some have cell walls (fungi and plants)

What lead to all species on earth?

our common ancestor from 4 billion years ago

About how many species are there?

1 trillion

Natural Selection

process of gradual change that occurs over time, individual organisms vary from each other

What is the main mechanism behind evolution?

natural selection

Evolution misconceptions

evolution is not a series of steps leading to increased complexity, there us no pressure on "lower" organisms that led to evolution of higher organisms

What is the only cell visible to the human eye?

ovum, female egg cell

Average number of human cells in a person

30 trillion

how many pounds of bacteria are on you right now?

3-5 pounds

What did the Miller-Urey Experiment discover?

Experimentally produced a bunch of organic molecules, then used those to make more molecules and amino acids

Karolina Sputova and Irep Gozen

Protocells spontaneously form of phospholipids on a mineral surface, inside where smaller bubbles (organelles), take up dyes (membrane transport)

RNA world hypothesis

self replicating RNA existed before evolution of DNA and Proteins

Last Universal common ancestor

most recent population of organisms from which all organisms descended

Stromatolites

layered sedimentary formations created by photosynthetic bacteria

Microfossils

fossils of microscopic life

What is found in both Eukaryotes and Prokaryotes?

Plasma Membrane and cell wall (think of plants)

Prokaryotes

bacteria and archaea

Eukaryotes

amoeba, yeast, multicellular plants, fungi, and animals

What are the common traits of ALL cells?

plasma membrane, cytoplasm, RNA and DNA, ribosomes

Cytoplasm

includes cytosol and organelles

Cytosol

watery, jelly like substance with salts and enzymes

Organelles

perform specific functions required by the cell, and work with other organelles (only in eukaryotes)

Plasma Membranhe

encloses all cells, determines materials to be allowed in or out, semi permeable

Embedded proteins

help transport substances through the plasma membrane, made of phospholipid bilayer

Phospholipid bilayer

hydrophobic tails interact with each other and keep the membrane together, exclude water, hydrophilic head maximize exposure to water

What organelle is only found in plant cells?

chloroplast

Cell Walls

provide extra protection outside the plasma membrane for plants, fungi and bacteria, rich in polysaccharides cellulose, provides structural support

Nucleus

holds chromatin in eukaryotic cells; surrounded by nuclear envelope; nuclear pores regulate traffic

Nucleolus

synthesizes ribosomes, inside of the nucleus

mitochondrion

produces energy through cellular respiration