AP BIO MIDTERM FLASHCARDS

Elements

Substances that cannot be broken down into simpler substances by chemical means.

Trace elements

Elements required by an organism only in very small quantities, such as iron (Fe), iodine (I), and copper (Cu).

Atoms

The unit of life and the building blocks of the physical world.

Protons

Positively charged (+) particles.

Neutrons

Uncharged particles.

Electrons

Negatively charged (-) particles.

Isotopes

Atoms that have the same number of protons but differ in the number of neutrons in the nucleus.

Compounds

Consists of two or more elements.

Chemical bonds

The forces that hold the atoms of a compound together, which may be ionic bonds, covalent bonds, or hydrogen bonds.

Ionic bond

Formed between two atoms when one or more electrons are transferred from one atom to the other.

Ions

Charged forms of the atoms.

Covalent bond

Formed when electrons are shared between atoms.

Non-polar covalent bond

A covalent bond where electrons are shared equally between the atoms.

Polar covalent bond

A covalent bond where electrons are shared unequally.

Hydrogen bonds

Weak chemical bonds that form when a hydrogen atom that is covalently bonded to one atom is attracted to another atom.

Cohesion

The tendency of water molecules to stick together.

Adhesion

The tendency of water molecules to stick to other substances.

Capillary action

The ability of water to rise up the roots, trunks, and branches of trees due to cohesion and adhesion.

Surface tension

The property of water that allows light things like leaves and water striders to sit atop the surface without sinking.

Acidic solution

A solution that contains a lot of hydrogen ions (H+).

Basic solution

A solution that releases a lot of hydroxide ions (OH-) when added to water.

pH scale

A scale numbered from 1 to 14 that measures the acidity or alkalinity of a solution, with 7 considered neutral.

pH formula

pH = -log [H+], indicating the concentration of hydrogen ions in a solution.

Organic molecules

Molecules that contain carbon.

Inorganic compounds

Molecules that do not contain carbon atoms.

Polymers

Chains of building blocks in macromolecules.

Monomers

The individual building blocks of a polymer.

Dehydration synthesis

A reaction where a water molecule is lost and a larger compound is formed.

Hydrolysis

The process where polymers are broken down into monomers by the addition of water.

Classes of organic compounds

Four classes central to life on Earth: carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Organic compounds that contain carbon, hydrogen, and oxygen in a ratio of approximately 1:2:1.

Types of carbohydrates

Categorized as either monosaccharides, disaccharides, or polysaccharides.

Saccharides

The term saccharides means 'sugar.' The prefixes refer to the number of sugars in the molecule.

Monosaccharides

It is an energy source for cells.

Glucose

The two most common sugars are glucose and fructose. Their chemical formula is C6H12O6.

Fructose

The two most common sugars are glucose and fructose. Their chemical formula is C6H12O6.

Photosynthesis

Glucose is an important part of the food we eat, and it is the product made by plants during photosynthesis.

Glycosidic Linkage

When two monosaccharides are joined, the bond is called a glycosidic linkage, and the resulting sugar is called a disaccharide.

Disaccharide

The disaccharide formed from two glucose molecules is maltose.

Polysaccharides

Polysaccharides are made up of many repeated units of monosaccharides.

Starch

Glycogen and starch are sugar storage molecules. Glycogen stores sugar in animals and starch stores sugar in plants.

Cellulose

Cellulose, on the other hand, is made up of β-glucose and is a major part of the cell walls in plants. Its function is to lend structural support.

Chitin

Chitin, a polymer of β-glucose molecules, serves as a structural molecule in the walls of fungus and in the exoskeletons of arthropods.

Proteins

Proteins are important for structure, function, and regulation of your tissues and organs.

Amino Acids

Amino acids are building blocks of proteins. They contain carbon, hydrogen, oxygen, and nitrogen atoms. There are 20 different amino acids.

Primary Structure

The linear sequence of the amino acids is the primary structure of a protein.

Secondary Structure

When the polypeptide begins to twist it begins forming either a coil (known as an alpha helix) or zigzagging pattern (known as beta-pleated sheets). These are secondary structures.

Tertiary Structure

When the secondary structure reshapes the polypeptide, amino acids that were far away in the primary structure arrangement can now also interact with each other. This is called the tertiary structure.

Quaternary Structure

When different polypeptide chains sometimes interact with each other, they form a quaternary structure.

Haemoglobin

Haemoglobin is a molecule in the blood that helps distribute oxygen to the tissues in the body. It is formed when four separate polypeptide chains interact with each other and is a quaternary structure.

Lipids

This consists of carbon, hydrogen, and oxygen atoms.

Triglycerides

The most common examples of lipids are triglycerides, phospholipids, and steroids.

Adipose Tissue

Our bodies store fat in tissue called, adipose, which is made of cells called adipocytes; these cells are filled with lipids called triglycerides.

Glycerol

Each triglyceride is made of a glycerol molecule (also called the glycerol backbone) with three fatty acid chains attached to it.

Fatty Acid Chain

A fatty acid chain is covered in hydrogen. One end of the chain has a carboxyl group.

Saturated Fatty Acid

A fatty acid that can be saturated with hydrogens along its long carbon chain.

Unsaturated Fatty Acid

A fatty acid that has a double bond in the chain.

Lipid Saturation

The extent of saturation in a lipid, affecting its structure and function; more double bonds mean more unsaturation.

Phospholipids

Molecules that contain two fatty acid 'tails' and one negatively charged phosphate 'head'.

Hydrophobic

A property of the fatty acid tails of phospholipids that are non-polar and do not mix well with water.

Hydrophilic

A property of the phosphate 'head' of phospholipids that mixes well with water due to its negative charge.

Amphipathic Molecule

A molecule that has both a hydrophilic region and a hydrophobic region, such as a phospholipid.

Cholesterol

A four-ringed molecule found in membranes that increases membrane fluidity and is important for hormone and vitamin D production.

Nucleic Acids

Molecules made up of nucleotides that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.

DNA

A nucleic acid that contains the hereditary 'blueprints' of all life.

RNA

A nucleic acid that is essential for protein synthesis.

Cell

The basic unit of structure and function in living things.

Surface Area-to-Volume Ratio

A concept that decreases as cells increase in volume, affecting material exchange efficiency.

Light Microscopes

Instruments used to study stained or living cells, capable of magnifying up to 1,000 times.

Electron Microscopes

Instruments used to study detailed structures of a cell that cannot be easily seen by light microscopy.

Prokaryotic Cells

Smaller and simpler cells, examples include bacteria and archaea.

Cytoplasm

The substance filling the inside of a prokaryotic cell.

Nucleoid

The region in a prokaryotic cell where the genetic material is found, consisting of one continuous, circular DNA molecule.

Cell Wall

A structure composed of peptidoglycans that surrounds the plasma membrane in most prokaryotes.

Eukaryotic Cells

More complex cells that include fungi, protists, plants, and animals.

Organelles

Smaller structures within eukaryotic cells, some of which are also found in prokaryotic cells.

Plasma Membrane

The outer envelope of the cell, made mostly of phospholipids and proteins, regulating substance movement.

Semipermeable Membrane

A membrane that allows certain substances to pass while blocking others.

Peripheral Proteins

Proteins loosely associated with the lipid bilayer, located on the inner or outer surface of the membrane.

Integral Proteins

Proteins firmly bound to the plasma membrane, which are amphipathic.

Transmembrane Proteins

Integral proteins that extend all the way through the membrane.

Fluid-Mosaic Model

The arrangement of phospholipids and proteins in the plasma membrane.

Fluid-mosaic model

This arrangement of phospholipids and proteins.

Adhesion proteins

Proteins that form junctions between adjacent cells.

Receptor proteins

Proteins such as hormones that serve as docking sites for arrivals at the cell.

Transport proteins

Proteins that form pumps using ATP to actively transport solutes across the membrane.

Channel proteins

Proteins that form channels allowing the selective passage of certain ions or molecules.

Cell surface markers

Glycoproteins and some lipids, such as glycolipids, exposed on the extracellular surface that play a role in cell recognition and adhesion.

Carbohydrate side chains

Chains found only on the outer surface of the plasma membrane.

Nucleus

Usually the largest organelle in the cell, responsible for directing cell activities and housing DNA organized into chromosomes.

Nucleolus

The most visible structure within the nucleus where rRNA is made and ribosomes are assembled.

Ribosomes

Sites of protein synthesis composed of two subunits, made of ribosomal RNA (rRNA) and proteins.

Endoplasmic Reticulum (ER)

A continuous channel extending into many regions of the cytoplasm providing mechanical support and transportation.

Rough ER

The region of the ER that has ribosomes and compartmentalizes the cell.

Smooth ER

The region of the ER that lacks ribosomes, making lipids, hormones, and steroids, and breaking down toxic chemicals.

Golgi Complex

Modifies, processes, and sorts products synthesized by ribosomes on the rough ER.

Vesicles

Little sacs that carry products to the plasma membrane.

Mitochondria

Power stations responsible for converting energy from organic molecules into useful energy for the cell, primarily ATP.

Cristae

Folds formed by the inner mitochondrial membrane that separate the matrix from the inter-membrane space.

Lysosomes

Sacs carrying digestive enzymes used to break down old organelles, debris, or large ingested particles.