Intro to Biology

• Biology is the study of life, examined from the largest scale (biosphere) to the smallest (molecules and atoms of organisms).
• The biosphere includes all Earth organisms and their environmental interactions.
• Ecosystems encompass all organisms in an area plus the non-living environment.
• An organism is a living entity.
• Organs and organ systems exist within complex organisms.
• Tissues include muscle, connective, nervous, and epithelial types.
• Cells, the fundamental units of life, are enclosed by a cell membrane.
• Organelles are cell structures that perform specific functions.
• Molecules consist of two or more atoms.
• Atoms are the smallest unit of an element, all having the same number of protons, but isotopes of the same element differ in neutron count.

Living vs Non-Living

• Distinguishing living from non-living can involve recognizing specific criteria, either through identifying the criteria, or listing them.

Autotrophs vs Heterotrophs

• Autotrophs produce their own food, mainly through photosynthesis.
• Heterotrophs consume other organisms for energy.

Scientific Inquiry

• Science studies observable and measurable phenomena, excluding supernatural ones.
• Inaccurate past findings require revision and retesting with new data.
• A basic framework is used to answer questions via the scientific method.

Organic Molecules

• Organic molecules contain carbon, usually with hydrogen.
• Methane (CH4) is the simplest organic compound.
• The four main types of biologically essential organic macromolecules include carbohydrates, lipids (fats), proteins (amino acid chains), and nucleic acids (DNA and RNA).
• Molecular function is determined by the atoms, shape, size, and charges within the molecule structure.
• Cells are the smallest units performing life activities.
• All organisms are composed of at least one cell.
• Multicellular organisms are eukaryotes, including plants, fungi, and animals.
• The plasma membrane defines each cell, regulating its interactions with the environment and maintaining homeostasis.

Cell Size Limits

• Genome limits the managed cytoplasm.
• Cytoplasm volume increases faster than the plasma membrane in larger cells.
• Voluntary muscle cells can be large and multinucleated.

Genetic Information

• Genetic information is encoded in nucleic acids, DNA and RNA.
• Prokaryotes are single-celled, while eukaryotes are single or multi-celled.
• Biologists have identified more than 2 million organisms.
• Taxonomists use evolutionary trees to show species relationships.
• The three domains of life are: Bacteria, Archaea, and Eukaryotes.
• Animals, plants, protists, and fungi belong to Eukaryotes.
• Protists are typically single-celled eukaryotes like amoebas, euglena and paramecia.
• Animals, plants, and fungi evolved clonally from protist colonies.

Homeostasis/Evolution

• Homeostasis maintains stable internal conditions needed for life functions.
• Biological evolution accounts for the unity and diversity of life.
• The Tully Monster fossil shows the unlikelihood of fossilization.
• Biological evolution changes species between generations.
• Darwin used artificial selection to understand natural selection.

Natural Selection

• Nature favors individuals with better characteristics, leading to species evolution.
• Darwin believed Galapagos tortoises showed adaptation to different habitats.
• Hypothesis-driven science explains nature, while observation science describes it, involving systematic observation.

Chemistry of Life

• Matter exists in solid, gas, and liquid.
• Elements cannot be broken down further by chemical reactions.
• Carbon, oxygen, hydrogen, and nitrogen make up about 96% of cell weight.
• Compounds contain atoms of two or more elements in a fixed ratio.
• Examples include NaCl (table salt) and H2O (water).

Atoms

• Protons and neutrons are found in the nucleus of an atom.
• Isotopes vary in neutron number; atoms of elements have the same proton number.
• Electrons are located in shells or orbits around the nucleus.
• Electrons determine the chemical properties and bonding behavior of atoms.
• Chemical bonds hold atoms together to form molecules, resulting from interaction in outermost layers.

Chemical Bonds

• Covalent bonds, where atoms share electrons to fill outer shells, form the strongest chemical bonds.
• Polar molecules, like water, result from uneven electron sharing.
• Hydrogen bonds arise from the polar nature of water, causing molecules to "stick" together.
• Negative oxygen ends attract positive hydrogen ends.
• Chemical reactions rearrange reactants into products.
• Chemical reactions involve electrons in the outermost shell of atoms.
• Chemical reactions rearrange but CANNOT create or destroy matter.
• The first life evolved about 3.7-4 billion years ago in the oceans.
• Water is the main compound in cells, accounting for most of our weight.
• Water molecules stick together, allow ice to float, resist temperature changes, and act as a common solvent.
• Water transports from soil through roots of plants.
• Floating ice insulates water, preventing freezing solid.
• Solutions consist of solvents and solutes, and aqueous solutions have water as a solvent.

Carbon and Macromolecules

• Lactose is the disaccharide of glucose and galactose that is the main sugar founds in milk.
• Lactase is the enzyme that is used to break down milk sugar.
• Humans that have acquired the ability to produce lactase throughout their lives have developed the trait due to the domestication of mammals and the use of their milk as food.
• People that stop breaking down lactase once they are no longer young break it down in their the large intestine, with lactase that has been produced by bacteria living in them.
• Carbon atoms can form covalent bonds with four other atoms.
• Cells are made of carbon compounds.
• Carbon comes from air and water, which plants uptake to construct sugars via photosynthesis.
• Polymers are molecules that are made up of subunits called monomers
• Polysaccharides have monomers of monosaccharides.
• Proteins have monomers of amino acids.
• Organisms can build and break down structures through digestion by using monomers they have digested to construct other macromolecules.
• Properties of organic compounds arise from the carbon skeleton, its shapes and sizes and atoms that have been attached to functional groups.
• Functional group roles give specific characteristics to organic compounds to work in chemical reactions.
• Large molecules break down via chemical processes.
• Monomers connect during chemical reactions to form large molecules like polypeptides/proteins.
• Carbohydrates, like sugars and sugar polymers are one of the four categories in which life depends.
• Carbohydrates are the primary source of energy for animals.
• Glucose is the monomer used to construct cellulose by plants and eukaryotic algae
• Cellulose is made up of wood, plants and cell walls.
• Monosaccharides are the simplest sugars.
• Glucose in monosaccharides is the main fuel to produce ATP in cells.
• In efficient conversions, monosaccharides are made efficiently into oxygen using processes that are aerobic and happen through cellular respiration.
• Disaccharides like lactose and sucrose are made up of monosaccharides.
• A disaccharide of a molecule of glucose like sucrose is called table sugar.
• Polysaccharides have a starch of glucose and are storage for plants.
• Glycogen is a polysaccharide in animals who use glucose to store energy.
• 0Cellulose is an organic compound used for building structures

Proteins/Enzymes

• Proteins are made from amino acid monomers
• The number determines how they function, determines the three-dimensional shape and function of a protein
• If an enzyme becomes damaged, it can become denatured and stop working properly
• Lipids are the category in which steroids belong in
• Sex hormones are not steroids like cortisol

Cell Theory

• Two major concepts of cell theory
  • Living things will compose of one or more cells -Cells come from cells
• Prokaryotes and Eukaryotes are major cell categories in biology.
• DNA is the primary form of organization in a cell, usually in the form of chromosomes.
• The chromosomes are made up of chromatin and DNA that protect the proteins when it can be used to divide and express a gene

Cellular Functions

• Ribosomes translate molecule into protein through transcription
• Cytosol is the fluid in the cell which helps by mostly being made up of water.
• Organisms first evolved around 3.7 and 4 billion years ago.
• The membrane physically divides cells in all organisms
• The the categories are smaller than the others
• A eukaryote contains inside a the cell-membrane and includes a fluid organelles
• Proteins in algae and plants are part of the of the membrane
• Proteins will transport through cells and through membranes
• Materials can move by going in being opened by polymers
• Chromatin protects molecules
• Proteins translates using MRNA
• Each type of cell typically has 46 chromosomes
• Enzymes catalyze biology by the activation of energy
• The most organic type of molecule are proteins
• Enzymes becomes denatured and cease functioning
• Chloroplasts act as cellular power in protists
• ATP is a food high in cellular energy

Test your knowledge of fundamental biology concepts, including levels of organization, characteristics of life, and classification of organisms. Explore scientific inquiry, organic molecules, and the function of organelles.