Midterm Exam BIO 101

What are the 5 characteristics of Life

Organization, Energy Use, Homeostasis, Reproduction Growth and Development and Responsiveness

What are cells?

The smallest unit of life

Homeostasis

Maintenance of Internal consistency

Metabolism

The extraction of nutrients and energy from food

Irritability

ability to respond to the environment

What is the order of the Scientific Method?

Observation, Hypothesis, Experiment, Data, Conclusion

Independent Variable

the experimenter set this (X axis)

Dependent Variable

the measured outcome (Y axis)

Population

2 or more individuals of same species in an area

Community

All different populations that live together in an area

Ecosystem

all living (biotic) and non-living (abiotic) things within defined area that cover the planet in the biosphere

Where does energy originate

in an ecosystem flowing in one direction

Food Chain

a series of organisms that successively eat one another

Primary Producers

form the base of trophic structure (plants photosynthetic algae)

Herbivores

Eat plants only

Carnivores

Eat animals only

Omnivores

Eat plants and animals

Decomposers

break down dead and decaying plants and animals, (ex. fungi, bacteria, insects and worms)

Natural Selection

Also called “the survival of the fittest” is the elimination of individuals whose inherited characteristics make it more difficult to survive

Evolution

The change in the phenotype of a population over time

Principle of superposition

fossils found in lower rock layers are older than those above

Charles Darwin’s observations

Organisms are inherited. Within a species, no two individuals are exactly alike.

S*xual selection

affects inherited traits that increase an individual’s chance of reproducing (ex. peacock feathers, horns in deer)

Microevolution

Evolution of emerging diseases over short time-frames (ex. months)

Macroevolution

Emerging diseases over millions of years

Atom

smallest component of an element which consists of protons and neutrons that make up the nucleus and electrons which surround the nucleus.

Proton

positively charged particle (+) (1au) in Nucleus)

Neutron

no charge (1 au) - in nucleus

Electron

negatively charged particle (orbitals) (0au)

Atomic number

the number of protons in the atom

Atomic mass

the total number of protons and neutrons in the nucleus

Isotopes

atoms of the same element but with different numbers of neutrons

Molecules

described by writing the symbols of their elements and indicating the number of atoms of each element as a subscript. (Ex. glucose is: C₆H₁₂O₆) (Ex. 6 C₆H₁₂O₆ means 6 molecules of glucose)

Chemical Reactions

These reactions are depicted as equations with the reactants or starting materials on the left and the end products on the right.

Example of a Chemical Reaction

CO₂ + 6H₂O => C₆H₁₂O₆ + 6O₂

Chemical Bonds

Atoms join to form molecules through attraction

Valence Electron

The number of electrons in the outer layer

Chemical bonds

Covalent and ionic

Covalent Bond

form when two atoms share valence electrons

Ionic bond

takes an electron away from another atom (no sharing)

Nonpolar covalent

occur when the electrons are shared equally (ex. methane, CH4)

Polar covalent

electrons are not shared equally

Hydrogen Bonds

weak and occur between water molecules that form and break constantly.

Hydrophilic

molecules attached to water

Hydrophobic

molecules are repelled by water

Cohesion

strong attraction between water molecules

Adhesion

Water forming hydrogen bonds with other compounds

Imbibition

the ability to absorb water (through it’s adhesiveness) and swell

Solvent

a chemical in which solutes, dissolve

Solution

consists of one or more chemicals dissolved in a solvent

Aqueous solution

water is the solvent

Hydronium

H₃O or H⁺

Hydroxide

OH⁻

pH scale

measures the H⁺ concentration to determine how acidic or basic a solution is.

Four Biological Macromolecules

Monosaccharides, Disaccharides, Oligosaccharides, and Polysaccharides

Monosaccharide

the monomer (smallest form) of carbohydrate (Ex. Glucose, Galactose, and Fructose) The main energy source for cells.

Disaccharides

Sucrose made from glucose and fructose, found in sugarcane and beets.

Lactose made from glucose and galactose, found in milk.

Oligosaccharides

Short sugar chains have an important role in immunity

Polysaccharides

Complex carbohydrates

Cellulose

large glucose polymer that forms wood

Chitin

large glucose polymer that forms the outer covering of insects, shellfish, and fungi cell walls.

Glycogen

Stored form of glucose in the liver and muscles.

Lipids

Do not dissolve in water (ex. fats, oils, feathers and fur)

Triglycerides

consists of a 3 carbon alcohol (glycerol) from which fatty acids extend

Saturated fatty acid

contains all the hydrogens it can, ie single bonds, are solid at room temperature and are the least healthy

Polyunsaturated fatty acid

more than one double bond and less Hydrogen (liquid at room temperature)

Proteins

Consist of monomers of amino acids linked to form polypeptide chains that make up structural molecules such as hair, skin, feathers, beaks, horns and muscle, as well as functional molecules like antibodies, hormones, neurotransmitters and enzymes.

Amino acids

A central carbon atom bonded to a hydrogen atom, a carboxyl group (COOH), an amino group (NH2), and a side chain called the R group

Nucleic Acids

Involved in heredity and the control of cellular activities

DNA (polymer of nucleotides)

Deoxyribonucleic Acid (double-stranded) (AGCT)

RNA (polymer of nucleotide)

Ribose (single-stranded) (AGCU)

Nucleotide

composed of a sugar, a phosphate group, and a nitrogenous base

Prokaryote

cells with a cell wall that lack nuclei and membrane-bound organelles (ex. bacteria)

Eukaryote

have nuclei that contain the DNA and associated proteins

Nucleus

Where DNA is stored and replicated and surrounded by the nuclear membrane which has pores

Nucleolus

inside the nucleus where ribosomes are made

Ribosomes

made of proteins and RNA and are the sites at which amino acids are combined to form proteins

Cytoplasm

the gel-like fluid inside cells

Rough ER

The ribosomes (proteins) that are formed either get incorporated into the cell membrane or will be expelled (Ex. Milk)

Smooth ER

where lipids are synthesized and added to the new proteins

Free ribosomes

proteins are used within the cell

Vesicles

are “sacs” made of new proteins which transport materials throughout the cell

Golgi bodies

a stack of flat sacs where carbohydrates are combined

Mitochondria

“power house” of the cell, where energy (ATP) is made from glucose by enzymes

Lysosomes

“garbage disposals” - they break down worn out organelles and contain many digestive enzymes in an acidic environment

Peroxisomes

Membrane bound sacs that contain catalase enzyme

Catalase enzyme

speeds up the conversion of hydrogen peroxide into water and oxygen

Centrioles

Involved in animal cell division (not found in plant cells)

Chloroplasts

House the chemical reactions of photosynthesis and chlorophyll (not found in animal cells)

Vacuole

Located sac for water storage and enzyme reactions (common in plants)

Cell Wall

Gives rigidity to cell (structured support) (only plants and prokaryotes)