BC Biology 12- cell biology

Matter

Flashcard

This refers to substances that can exist in various states, such as solid, liquid, and gas. It is made up of atoms and molecules and is fundamental to physical science.

Elements

Substances that cannot be broken down into simpler substances by chemical means. They consist of atoms, which are the basic units of matter.

• Each has a unique number of protons in its nucleus, defining its properties and position on the periodic table. Elements combine to form compounds and play crucial roles in chemical reactions.

• Examples include oxygen, gold, and iron.

Atoms

Subatomic particles such as the proton, electron, and neutron.

• Ex. Carbon (C), Nitrogen (N)

Proton

The proton is a subatomic particle with a positive electrical charge.

• They are found in every atomic nucleus of every element

Neutron

An uncharged elementary particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus.

Electron

A stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

Molecule

Two or more atoms combined to form a molecule

• Ex. water, amino acids

Compound

A chemical compound is a chemical substance composed of many identical molecules containing atoms from more than one chemical element held together by chemical bonds.

• A molecule consisting of atoms of only one element is therefore not a compound.

Ionic bond

Ionic bonds are formed when electrons are transferred between a metal and a non-metal element. As atoms gain or lose electrons, they become charged particles called ions.

• generally found in salts

• Ex. NaCl

Covalent bond

Covalent bonds form when electrons are shared between two non-metal elements

• Each atom has an octet of electrons in its valence shell (or 2 electrons in the case of hydrogen)

• When the sharing of electrons between two atoms is equal, the covalent bond is said to be a nonpolar covalent bond

• Ex. CO2

Polarity

Polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.

• Polar molecules must contain one or more polar bonds due to a difference in electronegativity between the bonded atoms

Hydrogen bond

A hydrogen bond is primarily an electrostatic force of attraction between a hydrogen atom which is covalently bonded to a more electronegative "donor" atom or group, and another electronegative atom bearing a lone pair of electrons—the hydrogen bond acceptor.

Hydrophilic

A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.

• Hydro- water

• Philic- loving

Hydrophobic

Hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water.

• Hydrophobic molecules tend to be non-polar

• They only dissolve in oil-based substances

• Hydro-water

• Phobic-fearful

Acid

Acids are substances that dissociate in water, releasing hydrogen ions (H+)

• acidity of a substance depends on how it fully dissolves in water

• Strong acid/ Hydrochloric acid (HCI) dissolves almost completely (HCI= H+ + CL-)

Base

Bases are substances that either take up hydrogen ions (H+) or release hydroxide ions (OH-)

• Strong base/ Sodium hydroxide (NaOH) dissociates almost completely

pH scale

The pH scale is used to indicate the acidity or basicity (alkalinity) of a solution

• traditional scale ranges from 0-14

• pH of 7 represents a neutral state, hydrogen ion and hydroxide ion concentrations are equal

• below 7 is an acid

• above 7 is a base

Buffer

A buffer is a chemical or combination of chemicals that keeps pH within a specific range

• living organisms maintain pH within a narrow range 7.35 to 7.45

• if pH drops, acidosis results

• if pH rises, alkalosis occurs

• mechanism to maintain pH

Homeostasis

The self-regulating process by which biological systems maintain stability while adjusting to optimal conditions for survival.

• regulated by positive and negative feedback loops

• disruption in homeostasis often lead to diseases or disorders

• Ex. Body temperature and blood pressure

Organic molecule

• Essential to human functioning

• they must contain carbon

• almost always contain hydrogen

• also known as biological molecules

• the smallest organic molecule is methane (CH4)

Functional groups

Specific combination of bonded atoms that always react in the same way.

Monomer

Basic units or building blocks of organic compounds

Polymer

Monomers that repeat over and over to form larger molecules

• aka macromolecules

Dehydration synthesis

The making of a polymer through H2O removal

• the building of biological molecules

Hydrolysis

The splitting of a bond using H2O

• the breaking down of biological molecules

Carbohydrate

Function

• quick fuel

• short-term energy storage

• structural role in woody plants, bacteria, and animals

• cell-to-cell recognition

Monosaccharide

• consist of monomer subunits called monosaccharides

• often called simple sugars

• readily dissolve in water

• end in -ose

Pentose

5-carbon sugar (C5 H10 O5)

• ribose (in RNA)

• deoxyribose (in DNA)

Hexose

6-carbon sugar (C6 H12 06)

• glucose (blood sugar, vital reactant for cellular respiration)

• fructose (found in fruits and honey)

• galactose (found in milk)

Disaccharide

• are made by dehydration synthesis

• 2 monosaccharides bonded together

• glucose + glucose = maltose (“malt sugar”)

• glucose + fructose = sucrose (common table sugar)

• glucose+ galactose= lactose (found in milk)

Polysaccharide

• is a carb that contains a large number of monosaccharide

• linked together by dehydration synthesis

• often called complex carbs

• polysaccharides are the form in which living things store excess sugar

• Starch (storage form of glucose in plants) is unbranched or slightly branced

• Cellulose/dietary fibre (used as a structural material in the cell walls of plants) is linear

• Glycogen (storage form of glucose in animals) is highly branched

Lipids

Function

• contains more energy than carbs

• long-term energy storage

• main component of cell membranes

• many types of hormones

• insulates against heat loss

• forms a protective cushion around major organs

• waxes prevent water loss and minimizes contaminants

Fats

• saturated fatty acid

• animal in origin (lard)

• solid at room temperature

Oils

• unsaturated fatty acid

• plant in origin (olive oil)

• liquid at room temperature

Glycerol

• one of the 2 subunits of lipids

• “backbone”

• 3-carbon compound with 3 -OH groups

Triglyceride

• common lipid

• also referred to as a neutral fat

• has 3 fatty acid chains attached to a glycerol molecule

• is formed by dehydration synthesis

Saturated fatty acid

• no double bonds between the carbons

• contain as many hydrogens as they can hold

• Ex. fat (lard)

Unsaturated fatty acid

• does have double bonds in the carbon chain which reduces the number of hydrogen atoms

• Ex. oil (olive oil)

Phospholipid

• important lipid

• tend to form a bilayer

• are essential the structure and function of cell membranes

• phospholipids are basically triglycerides except that in place of the 3rd fatty acid, there is a polar phosphate group

• The polar phosphate group is the hydrophilic head

• The 2 fatty acids become the non-polar hydrophobic tails

Steroid

• classified as lipids

• distinctly different structure

• composed of 4 fused carbon rings

• each type differs by the types of functional groups attached to the carbonskeleton

• Cholestrol (provides structural stability)

• Testosterone and Estrogen (reproductive system hormones)

Protein

Functions

• Metabolism

• Support (keratin and collagen give strength to ligaments, tendons, and skin)

• Transport (channel and carrier proteins allow substances to travel through the cell membrane)

• Defense (antibodies prevent antigens from destroying cells and disrupting homeostasis)

• Regulation (insulin regulates how much glucose is in the blood)

• Motion (actin and myosin allow parts of the cell to move)

Amino acid

• amino acid monomers construct protein polymers

• composed of a central carbon atom bonded to a hydrogen, amine group (-NH2), carboxyl group (-COOH), R

Amine group

• (-NH2)

• The amine group is a functional group that is composed of a nitrogen atom that is forming a total of three bonds: One bond with the parent organic chain. Two different bonds with either a hydrogen atom or an alkyl group R.

Carboxylic acid group

• (-COOH)

• Carboxyl groups are a combination of two functional groups attached to a single carbon atom, namely, hydroxyl (single-bonded OH) and carbonyl (double bonded O) groups.

R-group

• R (variable)

• R has 20 variations that can be polar, non-polar or ionized

Enzymes

• act as biological catalysts which speed up chemical reactions in cells

Hormones

Hormones are chemical substances that act like messenger molecules in the body.

• After being made in one part of the body, they travel to other parts of the body where they help control how cells and organs do their work

• Ex. growth hormone, insulin, melatonin

Hemoglobin

Hemoglobin (Hb) is the protein contained in red blood cells that is responsible for delivery of oxygen to the tissues.

Dipeptide

Two amino acids bonded together

Polypeptide

Many amino acids linked together

Peptide bond

Amino acids are linked by dehydration reactions that link the carboxyl group of one amino acid to the amine group of another

• the covalent bond that forms is a peptide bond

Primary structure

The linear sequence of amino acids, coded for in the genes of DNA, held together by peptide bonds

Secondary structure

Alpha helix or beta pleated sheet, caused by hydrogen bonding between amino acids

Tertiary structure

Interaction of amino acid side chains with water along with hydrogen bonds, ionic bonds and covalent bonds between the R groups leads to the final 3D structure of proteins.

• Most enzymes display this level of structure and can be denatured by high temperature or changes in pH

Quaternary structure

Occurs when two or more folded polypeptides interact to perform a biological function

Denaturation

• process modifying the molecular structure of a protein.

• Denaturation involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule that are responsible for the highly ordered structure of the protein in its natural (native) state.

Nucleic acids

Function

• Each cell has a storehouse of information that specifies how a cell should behave, respond to the environment, and divide to make new cells

• Nucleic acids are large biomolecules that play essential roles in all cells and viruses. A major function of nucleic acids involves the storage and expression of genomic information.

• Deoxyribonucleic acid, or DNA, encodes the information cells need to make proteins.

Nucleotide

• nucleotide monomers make up nucleic acids

• they are composed of three types of molecules; pentose sugar (either deoxyribose is DNA or ribose in RNA), phosphate group (phosphoric acid), nitrogenous base

Nitrogenous base

DNA- adenine, thymine, guanine and cytosine

RNA- adenine, uracil, guanine and cytosine

Phosphate

A form of phosphoric acid, which contains phosphorus

Pentose sugar

DNA- deoxyribose

RNA- ribose

Deoxyribonucleic acid (DNA)

• stores information about how to replicate itself

• specifies the order in which amino acids are to be joined to make a protein

Double helix

• two strands of DNA twist around each other to form a double helix

Sugar-phosphate backbone

The sugar-phosphate backbone is a chain of alternating phosphate groups and deoxyribose sugars that holds together a series of different nucleotides

• nucleotides are joined into a DNA or RNA polymer by a series of dehydration reactions, this results in a linear polymer called a strand

Complementary base sharing

Complementary base pairing in DNA refers to the specific pairing of nitrogenous bases:

• Adenine (A) pairs with Thymine (T).

• Cytosine (C) pairs with Guanine (G)

Adenine (A)

• double ring structure with nitrogen atoms

• it is a purine nucleotide base

Thymine (T)

• Also known as 5-methyluracil, thymine pairs with adenine (A) in DNA

• pyrimidine nucleobase

Cytosine (C)

• Cytosine has a heterocyclic aromatic ring, an amine group at position 4, and a keto group at position 2

• pairs with guanine

Guanine (G)

• guanine is paired with cytosine

• formula C5H5N5O

Ribonucleic acid (RNA)

Diverse type of nucleic acid with multiple roles in protein synthesis

• made up of adenine, uracil, guanine and cytosine

Uracil (U)

• uracil binds to adenine via two hydrogen bonds

• weak acid

• it is very resistant to oxidation and so it allows the RNA to exist outside of the nucleus freely without any hassle. This DNA can’t do.

Adenosine triphosphate (ATP)

It is a special high-energy nucleotide that acts as the universal energy currency of the cells

• it has three phosphate groups

• the bonds of the last 2 phosphate groups are unstable and easily broken

Adenosine diphosphate (ADP)

In cells, hydrolysis of the terminal phosphate produces the molecule ADP as well as a lot of energy

Monosaccharide (Glucose)

Disaccharide (maltose)

Polysaccharide (starch)

Polysaccharide (cellulose)

Polysaccharide (Glycogen)

Glycerol

Saturated fatty acid

Unsaturated fatty acid

Steriod

Phospholipid

Amino acid

Polypeptide (protein)

Nucleotide

DNA

RNA

ATP