Biology: the study of life

Living organisms can either be: unicellular or multicellular

Unicellular: forms of life that consist of a single cell

Multicellular: forms of life that consist of multiple cells

How many characteristics of life? 8

What are the 8 characteristics of life? Composed of cells, have order/organization, respond to their enviornment, regulation/homeostasis, reproduction, use energy, contain genetic information, evolve and adapt

Salt concentration in blood remains relatively steady, regardless of a person's diet. This best illustrates: homeostasis

Smallest scale of life: atoms

Largest scale of life: biosphere

Rank the multiple parts of life from smallest to largest: atoms, molecules, organelles, cells, tissues, organs, organ system, species, population, community, ecosystem, biosphere

Emergent properties: when living things become more and more complex as it goes from cellular level to organ systems “the whole is greater than the sum of the parts”

At which point of the organizational hierarchy does life emerge? The cellular level

Cells: smallest unit of life

Adaption: process that enables organisms to improve survival and reproduction in their environments, this is a result of natural selection

Fitness: an organisms ability to SURVIVE and REPRODUCE

Natural selection: “survival of the fittest”

2 requirements of natural selection: (1) genetic diversity, (2) differential reproductive success where individuals leave more offspring than others

Evolution: changes in the DNA of a population over multiple generations and can occur through natural selection + responsible for life’s diversity

Evolution through natural selection will occur most rapidly for populations of plants that: reproduce sexually and live in an unstable enviornment

Taxonomy: branch of science that classifies, identifies & names organisms

Three domains of life: Bacteria, Archaea, and Eukarya

Prokaryotes: lacks a nucleus, unicellular, bacteria + archaea

Bacteria DNA: circular and found in a region called the nucleoid and have small ribosomes and divide by binary fission

Eukaryotes: uni or multicellular organisms that have a nucleus and other membrane bound organelles

Eukaryotic DNA: linear shape and found inside the nucleus has ribosomes and divides by mitosis and cytokinesis

4 Domains of Eukaryotes: animals, plants, fungi, protists

Scientific method starts with: an observation and a question

Prediction: expected outcome

Hypothesis: proposed and testable explanation for an observation that includes a prediction

Theory: testable and broad hypothesis supported by a large body of evidence

Control groups: help prevent false positives/negatives

Negative control: control group where no response is expected like placebo

Positive control: control group where a response IS expected

97% of the mass of more life is composed of: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, and Sulfur

Trace elements: required for life in small amounts

Shells closer to the nucleus are: lower in energy than in distant shells

Radioactive Isotopes: unstable isotopes that break down & emit energy in the form of rays or particles

Half-life: time it takes for half of all radioactive atoms in a sample to break down

Uses for Radioactive isotopes: in medicine and for radiometric dating of fossils

Intramolecular bonds: interactions between atoms within the same molecule

Intermolecular bonds: interactions between atoms of different molecules

Covalent bond: when two atoms come together to share electrons to fulfill the octet rule

Polar covalent bond: in order to reach stability, atoms share electrons to meet the illusion that each atom completes the octet rule

Hydrogen bond: when a hydrogen atom polar covalently bonded to one electronegative atom is attract to another negatively charged atom

Ionic bond: forms when metals lose and electron to the plasma field and the nonmental gains the electron and then they form a compound

Water: small polar molecule that has partial positive and negative charges

Emergent properties of water: cohesion, adhesion, surface tension, low density, high specific heat and vaporization, universal solvent

Cohesion: ability for water molecules to stick together

Adhesion: ability for water molecules to stick to other molecules that are not water

Surface tension: measure of difficulty in breaking the surface of a liquid with force

Emergent properties of water is because water is: polar and can mkae hydrogen bonds

Water adheres to: polar or charged objects

Solid ice is important because: it has lower density than liquid water and can float which insulates the liquid below and helps sustain life

Water’s specific heat: is high which allows water to resist temperature changes

Specific heat: the amount of heat required to raise or lower 1 gram of a substance 1 degree Celsius

Heat of vaporization (evaporation): amount of heat required to convert 1 gram of a liquid to a gaseous state

Water’s heat of vaporization: high heat of vaporization due to the abundance of hydrogen bonds

Universal solvent: how water is described because it can dissolve so many solutes

Solvent: substance that does the dissolving and it found in larger amounts

Solute: the substance that gets dissolved by the solvent found in smaller amounts

Solution: the combination of solute and solvent

Hydrophobic: a substance that does not have an affinity for water that is nonpolar and fears water

Hydrophilic: a substance that has an affinity/likes water and is polar and dissolves in water

What is the pH of blood: 7.4

Acids: increases a solution’s concentration of H+ ions

Bases: any chemical that decreases a solutions concentration of H+ ions

Buffers: created by combining any acid with a bicarbonate ion (HCO₃^-), they resist changes in pH when acids or bases are added to a solution, used to maintain homeostasis

Organic molecules: any molecules with covalently linked carbon and hydrogen atoms

Hydrocarbons: organic molecules that only contain hydrogen and carbon atoms

Properties of carbon: 4 valance electrons = 4 bonds, form covalent bonds with itself, found in all organic compounds

4 different ways carbon backbones vary: length, position of double bonds, branch points, linear vs ring

Ethane structure:

Propane structure:

1-Butene structure:

2-Butene structure:

Butene Structure: 2-Methylpropane structure:

Cyclohexane structure:

Benzene structure: Functional groups: groups of atoms that are reactive/functional and commonly found together that typically extend off the backbone

Hydroxyl group (alcohol): R-OH

Carboxyl group (carboxylic acid):

Carbonyl group (ketones/aldehydes):

Amino groups (amine):

Sulfhydryl groups (thiol):

Phosphate group:

Methyl group:

Biomolecules: organic molecules that are essential to living organisms

What are the 4 biomolecules? Carbohydrates, lipids, proteins, nucleic acids

Carbohydrates: sugars and polymers of sugars that provide structural support and are used for energy storage

Lipids: does not have polymers, mix poorly with water, and consists of mostly hydrocarbon regions, and includes fats, phospholipids, and steroids

Proteins: chains of amino acids linked together by peptide bonds

Nucleic acids: DNA and RNA

Monomers: single individual building blocks that can be linked together to create polymers

Carbohydrate monomer: monosaccharide (glucose & fructose)

Glucose structure:

Fructose structure:

Carbohydrate polymer: disaccharides and polysaccharides

Disaccharide: formed by dehydration reaction which joins 2 monosaccharaides through a glycosidic linkage

Glycosidic bonds: covalent bonds that link monosaccharides together

Sucrose: glucose + fructose

Maltose: glucose + glucose

Polysaccharide: starch (glucose monomers), glycogen, cellulose, chitin

Glycogen: how starch is stored in our human body

Starch: how energy is stored in plant cells

Cellulose: a major component of cell wall that is linked together by covalent bonds in plants that our body cannot break down

Lipid monomer: do not have monomers or polymers

Fats: long-term energy storage in animals & plants

Phospholipids: major component of cell membranes

Steroid: component of plasma membranes and hormones

Glycerol: three carbon alcohol with a hydroxyl group attached to each carbon

Triglyceride: created by joining 3 fatty acids and joining it to a glycerol by dehydration synthesis and is needed by our cells for energy

Steroids: lipids characterized by a carbon skeleton like cholesterol and have 4 fused carbon rings

Cholesterol: precursor from which other steroids and hormones are synthesized

Saturated fatty acid: maximum number of hydrogen atoms, no double bonds, and solid at room temperature

Trans-fat: chemically altered cis-fat that turns into plaques when not turned into ATP

Unsaturated fatty acid: have one of more double bonds, has a kink, and is liquid at room temperature

Phospholipid: consists of two fatty acids and a phosphate group attached to glycerol, tails are hydrophobic while the heads are hydrophilic

Protein monomer: amino acid

Amino acid: contains a central carbon and hydrogen, amino group, carboxyl group, unique “R” group

Protein polymer: polypeptide chain

Primary: order of amino acids

Secondary: formation of alpha helices of beta sheets and are caused due to hydrogen bonding between atoms of peptide backbone

Tertiary: overall 3D shape of a polypeptide chain

Quaternary: multiple polypeptide chains to form a single functional protein

Denatured protein: a non-functional protein that has altered its shape due to changes in pH, temperature, or salt concentration

Types of amino acids: enzymatic, immune, storage, transport, hormonal, receptor, contractile, structural

4 types of proteins: non-polar, polar, acidic, basic

Nucleic acid monomer: nucleotide

Nucleic acid polymer: have 5’ & 3’ ends and store/encode genetic information

DNA vs RNA: Dna is double stranded and contains deoxyribose sugar and uses the base thymine instead of uracil

What is the difference between the sugar group in DNA and the sugar group in RNA? The sugar group in DNA has one less hydroxyl group than the sugar group in RNA.

Nucleotide: consists of ribose sugar, phosphate base, nitrogenous base

Pyrimidines: cytosine, thymine, uracil and are single ringed

Purines: guanine, adenine and are double ringed

DNA: double helix with 2 anti-parallel strands connected by hydrogen bonding

RNA: acts as a template for synthesizing proteins and forms a single nucleotide chain

Dehydration synthesis: forms covalent bonds to link monomers together and build a polymer through the loss of a water molecule

Hydrolysis: cleaves covalent bonds to break down a polymer by separating a water molecule giving one chain and H and another an OH

Ribosomes: build proteins through the process of translation and can be free in the cytoplasm or bounded to the rough ER

Protein secretion: nucleus, rough & smooth ER, Golgi apparatus, cell membrane

Cellular digestion: lysosomes, peroxisomes, vacuoles

Energy related organelles: chloroplasts, mitochondria

Cytoskeleton: microfilaments, intermediate filaments, microtubules

Cell junctions: tight junctions, gap junctions, plasmodesmata

Endomembrane system: group of membrane bound organelles inside a eukaryotic cell that has the function of secreting protein and cellular digestion

What are the 7 organelles in the endomembrane system: nucleus, endoplasmic reticulum, golgi apparatus, transport vesicles, lysosomes & peroxisomes, vacuoles, and the cell membrane

Nuclear envelope: double-membrane that surrounds the nucleus and acts as a barrier

Nuclear pores: allow entry/exit into and out of the nucleus

Nucleolus: where ribosomes are assembled

Process of making proteins (short): DNA is transcribed into RNA which is translated into a protein

Rough ER: closer to the nucleus and has a ribosome covered surface in which proteins are folded and modified

Smooth ER: synthesizes lipids and detoxifies poisons in the body

Golgi apparatus: receives vesicles and repackages contents into vesicles for export

Recycling centers for the cell: central vacuole and lysosome

Mitochondria: organelle that synthesizes lots of energy for the cell, has its own DNA, 2 membranes, and a matrix that contains the DNA

Chloroplasts: green organelles that function as the site of photosynthesis in many plant cells

ATP: adenosine triphosphate: high energy molecule used to power cellular reactions

Cellular respiration: mitochondrial process that breaks down food sources like sugars & lipids to make ATP

Endosymbiotic theory: mitochondria and chloroplasts were once independently living bacteria then the aerobic bacteria (todays mitochondria) was engulfed by the anerobic host cell and cyanobacteria (todays chloroplasts) were also engulfed and over time evolved to create todays animal and plant cell

What component of the cytoskeletons do motor proteins use to transport vesicles? Microtubules

Cilia: short structures that are used to provide cell movement

Flagella: longer structure that move like a whip to provide cell movement

Tight junctions: membrane protein that links cells creating a leakproof barrier

Desmosomes: intermediate filaments that anchor neighboring cells together

Gap junctions: protein channels that connect the cytoplasm of two animal cells in which ions can travel

Plasmodesmata: gaps in the cells walls that connect the cytoplasm of two plant cells