Chapter 1 - Chemical Nature of Cells Flashcards
Amphipathic
Having polar and non-polar regions and therefore has a
difference in water solubility
Anticodon
A sequence of 3 nucleotide bases on a tRNA molecule that pairs
with the complementary bases of an mRNA strand during
translation at the ribosome
Carbohydrates
Organic compound consisting of a chain of carbon atoms to
which hydrogen and oxygen are attached in a 1:2:1 ratio (e.g.
sugars, starch, glycogen, cellulose)
Cholesterol
Increases rigidity
Decreases fluidity of molecules through
Condensation
polymerisation
A reaction whereby small molecules (monomers) are
chemically bonded together into a large linear or branched
molecule; a molecule of water is eliminated when tow
monomers are bonded together
Covalent bonds
Strong chemical bonds that form between non-metal atoms by
the sharing of pairs of outer shell electrons; bonds may be single
(one-pair), double (two pairs) or triple (three pairs)
Disaccharides
Two monosaccharide molecules joined by a glycosidic bond
DNA
Deoxyribosenucleic acid in a polymer of nucleic acids
Made up of deoxyribose sugar
Contain genetic coding information which codes for the production of proteins throughout the body
Glycolipids
A lipid molecule with an attached short chain carbohydrate; its
role is to provide energy or to serve in cell membranes as a
marker for cell recognition
Glycoproteins
A protein molecule with an attached carbohydrate chain
Glycosidic bond
The covalent bond between carbohydrates
Hydrogen bonds
A weak intermolecular chemical bond between a hydrogen atom
on one molecule and a second, more electronegative element,
usually an oxygen or nitrogen atom on another molecule;
hydrogen bonds are important
Hydrophilic
Polar Substances, with unequal charge distribution such as polar molecules and ionic compounds, which are soluble in water
Hydrophobic
Non-polar Molecules with equal charge distribution. Not soluble in water
Lipids
A general term for fats, oils and waxes; they are insoluble in
water and largely made of molecules containing C, H, O and at
times N and S
Monomer
A small molecule that acts as a building block for polymeric
macromolecules, such as glucose (for complex carbohydrates),
amino acids (for proteins) and nucleotides (for nucleic acids)
Non-polar
A molecule that disperses charge evenly; it lacks a particular
charged end
Nucleic Acids
Large polymers made up of nucleotides; deoxyribonucleic acid
and ribonucleic acid are the information-carrying molecules of
the cell and carry the instructions for making all the structures
and materials the body needs to function
Nucleoli
Granular structure within the nucleus where ribosomal RNA is
transcribes and ribosome subunits are assembled
Peptide bond
The bond that forms between two amino acid monomers with the elimination of a water molecule during condensation polymerisation
Polar
A molecule with an uneven distribution for charge giving it
distinct charged ends
Polymers
Large molecules built up from linking smaller molecules
together by the process of polymerisation
Proteins
A polymeric macromolecule built up of amino acids monomers;
proteins have specific structural and functional roles in living
things and are produced from the information encoded in an
organism’s genetic material
Proteome
The structure and properties of all the proteins produced by an
organisms genetic material (genome)
Bond formed during condensation polymerisation of Protein:
Peptide Bond
Bond formed during condensation polymerisation of Glycogen:
Glycosidic bond
3 Disaccardides and monomers
Maltose: Glucose *2
Lactose: Gucose & Galactose
Sucrose: Glucose & Fructose
4 polysaccarides and function
Cellulose: Fibre, tight linear, u branched arrangement of glucose
Chitin: Tough, cellulose like substance
Starch: Polymer made of glucose monomers linked in twisted chains (Plant energy storage)
Glycogen: Multi-branched polysaccaride of glucose (animal energy storage)
Amino acid structure
Carboxylic acid group
Amino group
R (variable) group
central carbon
Primary structure of Protein
- sequence of amino acids
Secondary structure of protein
- coils and folds due to hydrogen bonding
results in:
-alpha coils - beta sheets
Tertiary structure of protein
- 3 dimensional functional shape
Due to;
Hydrogen bonds, ionic bonds and disulphide bridges - determines function
Quaternary structure of protein
Complex proteins which consist of two or more polypeptides joined together by bondfs
Globular proteins Vs Fibrous proteins
Fib: water insoluble
- structure and support
Glob: water soluble
- transport, messenger, catalyst,
Roles of proteins
Structure: Enzynmes: Transport; carry molecules Hormones: Cell surface receptors: Neurotransmitters; Antigens: Poisons and Toxins:
Lipids:
non-polar and hydrophobic molecules
long carbon chain with carboxyl group at one end
not polymers
Saturated Vs unsaturated lipids
saturated: unbranched carbon chain fully “saturated” with hydrogen. No double bonds
Solids, animal fats
Unsaturated: kinked carbon chain, with double bonds. Usually liquid oils.
Triglyceride
- 3 fatty acids attached to glycerol backbone
- means of energy storage in animals
Phospolipids
lipids with glycerol backbone, two carbon chains and a phosphate head which mean molecule is especially polar.
How protein function is changed
Protein shape determines function
- Coding DNA determines sequence of amino acids
- By changing sequence of DNA/amino acids bonding between “R” groups changes.
- Excessive heat or acidity can denature protein by altering bonds and shape
Glycolipid
Glycogen group attached to glycerol backbone instead of fatty acid.
Vital for cell communication
Steroids
technically lipid but do not resemble them.
include cholesterol which help maintain cell rigidity and fluidity.
What is meant by the term “Polymerise”?
The formation of a polymer through the bonding of monomers in a condensation polymerisation reaction.
Glycoproteins role
It is a protein with producing carbohydrate. Glycoproteins play an important part in hormone function. The action of hormones depends on the initial binding of the hormone to a protein receptor molecule. In many cases this molecule is a glycoprotein
Glycolipids role
Glycolipids are lipids with a carbohydrate attached. Their role is to provide energy and also serve as markers for cellular recognition.
lipoporteins role
Complex of lipids and proteins which act as carriers for lipid soluble matter in the bloodstream.
role of lipid attachment to protein.
lipid attachment on protein can anchor the protein in the phospholipid bilayer,
Neutral fat
Neutral fats are produced by the dehydration synthesis (water released from fat) of one or more fatty acids with an alcohol like glycerol
Role of cholesterol
more flexible •
more stable •
more fluid in colder temperatures •
decrease the permeability of the bilayer to create small water-soluble molecules.
