BIOL1111 - General Biology 1: Exam One Review

Properties of life, scientific method, basic chemistry and chemical bonds, water, biomolecules, cell structure, membrane structure/function/transport, extracellular matrix, cell communication

Characteristics of Living Systems

Cells and organization, energy use and metabolism, response to environmental change, regulation and homeostasis, growth, development, & reproduction, evolution over time. Think
‘DOGRACE’: dna, organized, growth and development, reproduction, adapt and respond to environment, cells, and energy.

Defining life

All living things are comprised of the same chemical elements and obey the same physical and chemical laws as nonliving objects.

Biological Evolution

All living organisms descended from a common ancestor.

Unity

the shared characteristics of all living organisms, which are the result of common ancestry and evolution.

Diversity

the variety of life on Earth, including the variety of organisms, their interactions, and the ecosystems they live in.

Natural Selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring. Theory created by Darwin.

Adaptation

any modification that makes an organism suited to its way of life. Over time, organisms become. modified by the process of natural selection.

Aristotle

presented Scala Naturae, the “great chain of being” - first hierarchical structure of all matter and life. The father of taxonomy.

Linnaeus

Created “Systema Naturae” along with binomial nomenclature.

Darwin

proposed the theory of biological evolution by natural selection; decent with modification.

Taxonomy

science of identifying and classifying organisms (according to evolutionary relationships).

Phylogeny

Tree of life

Binomial nomenclature

Scientific name: (Genus species), universal, Latin-based

(largest) Domain, kingdom, phylum, class, order, family, genus, species (smallest)

Levels of biological organization

A cell is the smallest most basic unit of life.

(smallest) cell, tissue, organs, organ systems, organism (species), population, community, ecosystem, biosphere

Energy

The capacity to do work, flows through the biosphere

Metabolism

all of the chemical reactions in a cell, prominently ones that change food into energy

Anabolism

a biochemical process in metabolism where the simple molecules combine to generate complex molecules.

Catabolism

the breakdown of complex molecules in living organisms to form simpler ones with the release of energy. “destructive metabolism”.

Homeostasis

maintenance of internal conditions within certain boundaries; associated with dynamic equilibrium

ATP

Adenosine Triphosphate - primary energy currency of cells, used to transfer energy within living organisms to power cellular processes.

DNA

deoxyribonucleic acid; molecule found in cells that carries genetic information

Response to stimuli

A change in the activity or state of an organism or cell in response to a stimulus.

Rules of Science

obeys natural law, explained in reference to natural law, tentative, falsifiable.

Scientific method

Observation, hypothesis, prediction, experimentation, conclusion.

Discovery of penicillin

The first antibiotic discovered by Alexander Fleming in 1928. Left culture plates unwashed and cultures contaminated with mold Penicillium notatum. Received nobel prize in 1945.

Scientific theory

A related set of testable, well-supported hypotheses that form a broad explanation about aspects of the natural world.

Hypothesis

A tentative, testable explanation for what was observed.

Prediction

The expected result of any experiment if a hypothesis is supported

Chi-squared test/goodness of fit test

• Degrees of freedom: number of categories minus one

• Null and alternate hypothesis

• When P is more than .05, we accept the null hypothesis and we assume chance is responsible and that the difference is not significant.

• When P is less than .05, we reject the null hypothesis and we assume chance is not responsible and a significant difference exists.

• sums of (observed-expected) divided by (expected).

Chemical elements that make up 98% of all living organisms

Hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, calcium

Atomic symbol

a short notation of one or two letters representing an element.

Protons

positive charge (p+), found in the nucleus

Neutrons

neutral charge (n), found in the nucleus

Electrons

negative charge (e-), orbit the nucleus and determine chemical properties

Valence electrons

electrons able to combine with other atoms.

• equal to or less than three electrons = more likely to donate

• equal to or more than five electrons = more likely to recieve

Nucleus

Command center of cell, separated from cytoplasm by nuclear envelope (double layer of membrane), contains chromatin which has dna and condenses to form chromosomes

Nucleolus

composed of rRNA, produces subunits of ribosomes.

Energy shell

a specific region around an atom’s nucleus where electrons are most likely to be found, representing a distinct energy level that electrons can occupy

Atomic number

The number of protons in the nucleus, the number atop the atomic symbol when displayed.

Mass number

Also known as “atomic mass”, the number of protons plus the number of neutrons. The number below the atomic symbol when displayed.

Elements in the same _____ on the periodic table have the same number of and types of orbitals

row

Elements in the same _____ on the periodic table have the same number of outermost electrons

column

Isotopes

atoms of the same element where the proton number stays the same but the neutron number is different.

Radioisotopes

Isotopes that give off energy in the form of gamma rays or subatomic particles.

Tracers

reveal a pathway or destination of a substance that has entered a cell, the human body, or an ecosystem

Orbitals

where electrons occupy around a nucleus.

Bohr model

A display that puts electron shells as circles around the nucleus.

Octet rule

The innermost electron shell has two electrons, and the next two shells can have a maximum of eight electrons (8 e- = stability).

Molecule

two or more atoms bonded together

• If all atoms in a molecule are of the same element, it’s still an element

• If at least one atom is from a different element, it’s a compound.

Ionic bonding

Between an anion and a cation, becoming neutral: exchanging electrons

Covalent bonding

When two atoms share one, two, or three electrons (not permanently exchanged)

Polar covalent bond

unequally shared with some type of charge

Nonpolar covalent bond

Equally shared

Hydrogen bonding

Bonds between two water molecules when the partial positive charge of a hydrogen atom attracts the partial negative charge of the oxygen atom.

Carbon

Has four valence electrons, “the building block of life”. Can form four bonds.

Free radicals

Atoms with a single, unpaired electron in its outer shell. Very unstable, steals electrons from molecules. Creates new free radicals from donor molecules causing a chain reaction. Some molexules donate extra electrons to free radicals without becoming reactive.

Oxidative stress

Formed through exposure of cells to radiation, leads to cell damage.

Water chemistry

H2O, creates chains through hydrogen bonds

Hydrophobic

Repelling water

Hydrophilic

Attracted to water

Water properties

polar molecule, good solvent, neutral pH (7), less dense when solid than when liquid, resists increases or decreases in its temperature because hydrogen bonds would have to be broken, high surface tension.

Cohesion

Water is attracted to water

Adhesion

water is attracted to other substances

Organic versus inorganic biomolecules

Inorganic:

• chemistry of elements other than carbon

• usually with positive and negative ions

• Usually ionic bonds

• Always with few atoms

• Associated with nonliving matter.

Organic:

• Carbon-based chemistry

• Always containing carbon and hydrogen

• Always covalent bonds

• Often large, with many atoms

Functional groups

Specific groups of atoms within a molecule that give it unique chemical properties and reactivity.

Monomers

a molecule of any class of compounds that can react with other molecules to form polymers.

Polymers

large molecules consisting of many monomers

Hydrolysis

the addition of a water molecule to disassemble polymers

Dehydration synthesis

the removal of a water molecule to connect monomers

Biomolecules

lipids, nucleic acids, proteins, and carbohydrates

Carbohydrate function & properties

consist of carbon, hydrogen, and oxygen. Serve as an immediate energy source, energy storage molecules, structural components of cells. Most abundant organic molecules on earth, stores in liver and muscles through glycogen

Carbohydrate monosaccharides

simple sugars - soluable and sweet to taste

Carbohydrate disaccharide

sugars - soluable, sweet to taste. Important in the transport of sugars

Carbohydrate polysaccharide

branched and unbranched forms, low solubility, not sweet to taste, structural component, short-term energy storage (ex: starch, glycogen)

Glycosidic bond

a covalent chemical bond that connects a carbohydrate molecule to another group

Lactose

a sugar that is not absorbed and is metabolized by large intestine bacteria

Lactase

an enzyme that actively declines with age. Breaks down lactose. Not enough lactase can cause lactose intolerance.

Lipid function & properties

insoluble in water, not polymers. Long chains of repeating C2 units with oxygen, phosphorus, and nitrogen. Nonpolar, structural in cells and serve as energy reservers, messengers, insulation, and cushioning. Four types:

1. Fats: long term energy storage and thermal insulation in animals

2. Oils: long term energy storage in plans and their seeds

3. Steroids: component of plasma membrane, hormones

4. Waxes: wear resistance, retain water (nonpolar), high melting point

Triglycerides

fats and oils: long term energy storage, backbone of glycerol molecule (three fatty acids attached to each glycerol molecule).

• Saturated: no double bonds between carbons

• Unsaturated: more than or equal to one double bonds between carbons

cis-fatty acids

has it’s hydrogens on the same side of double bond, U-like form, most naturally occuring unsaturated fatty acids in food are cis

trans-fatty acids

has it’s hydrogens on opposite sides of the double bond, more linear, usually occurs in partially hydrogenated foods when hydrogen atoms shift around some double bonds and change from cis to trans.

Phospholipids

component of plasma membrane, a class of compounds found in all living organisms.

Eicosanoids

local hormones, produced by all cells of human body; essential for body

Waxes

wear resistance, retain water (ex. candles, polishes). long chains of fatty acids bonded to a long chain of alcohol: nonpolar. High melting point and waterproof.

Protein Function

Metabolism, defense, cell recognition, transport, structure, motion, osmotic regulation, and storage. Make up 20% of human body weight.

Protein structure

Made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. Polymers of amino acids, with each amino acid having a central carbon atom to which a hydrogen atom, amino group, carboxylic group, and one of twenty different types of side chain groups.

Peptide bond

formed by a combination of amino acids in which the group of one amino acid has undergone a reaction with the carboxylic acid of another amino acid.

Protein folding

Assembly of amino acids into protein is extremely complex, process is overseen by “chaperone molecules”. Defects in chaperones can corrupt the 30 structure of proteins, prominent diseases caused by folded proteins are Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease

Cystic fibrosis

autosomal recessive disease, inherited, caused by mutations in gene CF transmembrane regulator (CFTR)

Nucleic acids function

Storage and expression of genetic information in DNA and RNA.

Nucleic acids structure

Polymers of nucleotides, large complex organic molecules.

• DNA:

  • Double-stranded helical spiral (twisted ladder)

  • Serves as genetic information center in chromosomes

• RNA:

  • Part single stranded, part double stranded

  • In nucleus and cytoplasm of cell

  • three types: mRNA (messenger), rRNA (ribosomal), tRNA (transfer)

Nucleotides

Consist of phosphate group, pentose sugar (ribose or deoxyribose), and nitrogenous bases

Bases

in DNA:

• adenine

• thymine

• guanine

• cytosine

in RNA:

• adenine

• uracil

• guanine

• cytosine

Pairs match A-T (or A-U in rna) and G-C

Cell theory

all organisms are composed of cells

• life processes of metabolism and heredity occur within these cells

• new cells come only from preexisting cells

• cells are the smallest structural and functional unit of life

Cell size

most much smaller than one millimeter, some as small as one micrometer. Size is restricted by surface/volume ratio

• surface: membrane across which cell acquires nutrients and expels wastes

• volume: cytoplasm, which demands nutrients and produces wastes

• volume increases faster than surface

Prokaryotic cells

lack a membrane-bound nucleus and membrane-bound organelles. Small and simple, domains are bacteria and archea

Bacteria

ubiquitous, some pathogenic, some photosynthetic, some decompose organelles

Archea

more diverse, some in extreme habitats, closer to eukaryotes

Eukaryotic plant cells

have a cell wall in addition to a cell membrane, have a membrane-bound nucleus, contain chloroplast

Eukaryotic animal cells

have only a cell membrane, have a membrane-bound nucleus, have lysosomes