RAD 1031 exam revision

What are noncovalent interactions?

interactions that do not involve the sharing of valence electrons

- hydrogen bonds

- electrostatic interactions

- hydrophobic interactions

- van der waals

what are hydrogen bonds?

when a weak positive hydrogen atom is bonded to another electronegative atom to form a molecule (hydrogen donor and acceptor)

importance of hydrogen bonds?

- stabilise molecules

- maintain structure of alpha helix, b pleated sheet and DNA

what is a. electrostatic interaciton?

attraction or repulsion between molecules with electric charges

what is a hydrophobic interaciton?

between non-polar molecules in water

what is the van der waals interaction?

distance dependent reaction between atoms/molecules when they come close together.

what is the biological membrane structure?

lipid bilayer with proteins embedded and held together by non-covalent interactions.

- also has cholesterol

what is the structure of a phospholipid?

- polar/hydrophilic head (with phosphate and glycerol)

- non-polar/hydrophobic tail - fatty acid

is an acid a proton donor or acceptor?

donor

what are Amphipathic molecules

molecules that contain hydrophobic and hydrophilic regions (polar and non poler regions)

what types of proteins are associated with the cell membrane?

- integral

- peripheral

- channel (allow movement of water/hydrophilic solutes, can be open or gated - ligand, voltage, mechanical)

- carrier (can be open on either side, active or passive)

components of water:

2 (+ ) hydrogen and 1 (-) oxygen

- dipole cause one side is positive and one is negative

what bonds do water molecules form?

hydrogen bonds between oxygen atom of upper molecule and hydrogen atom of lower molecule.

- also form string cohesive bonds

what are polar biomolecules?

- they are hydrophilic and can dissolve in water by replacing water-water interactions with mire energetically favourable water-solute interactions

what are nonpolar biomolecules?

- they are hydrophobic and cant dissolve in water cause they interfere with water-water interactions and cant form water-solute reactions.

how does water dissolve Na and Cl?

- oxygen atom faces na and hydrogen atom faces Cl

what are the properties of water?

1. Good solvent

2. thermal stability

5. chemical Reactivity

6. cohesion and adhesion

Is Na high or low inside the cell?

low

is K high or low inside the cell

high

is Ca high or low inside the cell

low

structure of carbohydrates:

carbon, hydrogen, oxygen

- have an aldehyde or ketone group and a hydroxyl group

- composed of individual units called monosaccharides

what are monosaccharides?

simple sugars (glucose, fructose, galactose) that differ in the spatial arrangeme nt of atoms.

What are disaccharides? and what are they joined by?

sucrose, lactose, maltose

- when 2 monosaccharides are joibned by glycosidic bonds

what is the polysaccharide structure?

large linear and bracnhed molecules made from monoscaccarides

- more than thousand

- cellulose, starch and glycogen in animals/humans

what are the 3 main functions of carbohydrates?

1. energy source

2. structural

3. physiological functions

what are lipids?

- hydrophobic molecule composed of carbon, hydrogen and oxygen with a high ratio of hydrogen to oxygen.

what are the types of lipids?

triglycerides, phospholipids, steroids, fatty acids, eicosanoids

what are the functions of lipids?

long term energy storage

what are fatty acids?

A chain of usually 4 to 24 carbon atoms with a carboxyl group at one end and a methyl group at the other.

what are the types of fatty acids?

saturated (no double bonds)

unsaturated (one or more double bonds in hydrocarbon tail)

what are the cis and trans configurations in fatty acids?

the double bonds in saturated fats are either in a cis or trans configuration

- cis: the two hydrogens

associated with the bond are on the same

side and creates a bend in the fatty acid.

- trans: the two hydrogen

associated are on opposite sides.

what are triglycerides?

- formed by linking fatty acids with an

ester linkage to three alcohol groups in glycerol.

- are the form in which fat energy is stored in adipose tissue.

what are phospholipids?

- formed from Glycerol, Fatty acids and a phosphate group.

- composed of two fatty acids linked to glycerol

- The two fatty acid carbon chains may be

both saturated, both unsaturated, or one

of each.

What are eicosanoids?

biologically active lipids with local hormone-like activity

- 20 carbon compunds derived from a fatty acid

what is cholesterol?

blood fat produced by liver and most cells (type of steriod)

what are steroids?

have 4-ring like carbon structure with variation in their finctional groups

HDL vs. LDL cholesterol

HDL-good (prevents build up of plaque in vessles)

LDL-bad (blocks arteries, decreasing blood flow to the heart)

composition of proteins

- formed by different combinations of 20 amino acids

- proteins are polymers of amino acids joined by peptide bonds

- proteins contain one or more polypeptide chains (50 amino acids)

what are amino acids?

building blocks of proteins

amino acid structure:

- a carboxyl group (COOH - acid), amino group (NH2), R group

- amino and carboxyl groups are attached to a central/alpha carbon

- the alpha carbon contains a hydrogen atom and side chain (R group)

what are the different types of amino acids?

polar, nonpolar, acidic, basic

How are peptide bonds formed?

condensation reaction between 2 amino acids

- amino group of one AA reacts with the carboxyl group of another AA, releasing water

what are the 4 levels of protein structure?

primary, secondary, tertiary, quaternary

what is the primary structure of a protein?

sequence of amino acids in a polypeptide chain

what is the secondary structure of a protein?

when the promary structure formed a-helices or b-pleated sheets

- stabilised by hydrogen bonding between amino acids

a helix vs b pleated sheet

- A: r group points side ways

- B: alternatey point above and below the plane of the sheet

what is the tertiary structure of a protein?

3D structure including bending

what is the quaternary structure of a protein?

two or more polypeptide chains joined by noncovalent forces called subunits

what are the main functions of proteins?

enzymes, immunity, hormone synthesuis, nutrient trabnsport, cell signalling

how do proteins fold into a compact conformation?

- The nonpolar (hydrophobic) side

chains cluster in the interior of the

molecule.

- polar groups arrange

themselves near the outside of the

molecule, where they can form

hydrogen bonds with water and with

other polar molecules.

polar vs nonpolar

P = hydrophillic

NP = hydrophobic

protein denaturation

▪ This involves the loss of tertiary

and/or secondary structure as well

as biological function.

▪ Weak bonds break e.g. hydrogen

bonds.

▪ Protein structure can be denatured

by heat, changes in pH, and certain

chemicals

what are enzymes?

biological catalysts that speed up reactions

- they are reusable and are never destroyed

- they are specific to a chemical reaction

what is enzyme specificity?

enzymes bind specific readtions at the active site to form an enzyme substrate complex that releases a prodiucyt.

how does an enzyme lower activation energy?

It binds the substrate to react.

what are 4 charcteristics of enzymes?

1. work rapidly

2. dependent on ph (7 or 2 for pepsin in stomach)

3. dependent on temperature (37)

4. substrate specific

what are the types of enzymes?

- Oxidoreductases - catalyse the transfer of hydrogen or oxygen atoms or

electrons from one substrate to another e.g. Alcohol Dehydrogenase.

- Transferases - catalyse group transfer reactions (Transaminase).

- Hydrolases - catalyse hydrolytic reactions (Urease).

- Lyases - catalyse non-hydrolytic removal of functional groups from

substrates (Decarboxylase).

- Isomerases - catalyses isomerization reactions (Triosephosphate

isomerase).

- Ligases - catalyses the synthesis of various bonds (Glutamine synthetase).

what are enzyme partners?

Substrate can not fit in without the Coenzyme/Cofactor.

▪ Prosthetic group is a permanent part of the structure of the enzyme.

what are types of enzyme partners?

▪ Cofactors: inorganic ions e.g. metal ions, that help enzymes perform their

function. Some examples of cofactors include iron, zinc, and magnesium.

▪ Prosthetic Group: non-amino acid, tightly bound to enzymes, contributing to

their catalytic activity. Unlike coenzymes, prosthetic groups cannot be easily

removed from the enzyme e.g. heme, found in catalase.

▪ Coenzymes: organic cofactors, help enzymes catalyze reactions, derived

from niacin, riboflavin, and other water soluble vitamins e.g. NAD+

, FAD, and

coenzyme A.

what is the role of enzymes in metabolism?

- catabolism (breakdown of comples molecules into small ones (release energy - glycolysis)

- anabolism (synthesis of complex molecules from simple ones (need energy - gluconeogenesis)

how is glucose metabolised?

what are nucleotides?

building blocks of nucleic acids (DNA/RNA)

- consist of a sugar molecule, phosphate group and a nitrogenous base

difference between a nucleotide and a nucleoside?

Nucleoside does not have a phosphate group

what is the n-glycosidic bond?

The base is linked to the same carbon (C1) used in sugar-sugar bonds.

what are doexyribose and ribose sugars? and purpose of prime numbers

- 5 carbon sugar is called a pentose sugar

- The carbon numbers are given a prime (') designation for pentoses of nucleotides and nucleosides - to distinguish them from the numbered atoms of the nitrogenous bases

- Deoxyribose: oxygen has been removed. Used in deoxyribonucleic acid

- Ribose: used in ribonucleic acid

Differentiate between nucleotide and nucleoside bases:

- The nitrogenous bases are derivatives of two parent compounds - pyrimidine and purine (heterocyclic compounds)

- Pyrimidine: smaller than purine, has 1 ring structure, uracil, cytosine, and thymine.

- Purine: have double ring structure, adenine and guanine

what are nucleic acids? and what type of bonds link nucleotides/where does this occur?

- Both DNA and RNA contain two major purine bases; adenine and guanine

- Two major pyrimidines (cytosine in both), but the second is different (thymine in DNA and Uracil in RNA).

- Phosphodiester bonds (PB) link successive nucleotides in nucleic acids

- PB is between 5' and 3' carbon atoms to form nucleic acids

- The linear sequence of nucleotides is commonly abbreviated by as A-G-C-T-T-A-C-A, with the 5' end of the chain at the left

what is the structure of DNA backbone, in general and the prime ends?

- BACKBONE: DNA should have a 1:1 ratio of pyrimidine and purine (Guanine must be equal to cytosine, Adenine must be equal to thymine)

- Double helix

- Sugar phosphate are outwards

- Bases are inside the helix

- 5' - 3' ends are antiparallel

- Purine bases pair with pyrimidine bases (A/T and G/C)

- Hydrogen bonding patterns in base pairs stabilises DNA helix

what are the functions of nucleotides?

They carry chemical energy (ATP)

They combine with other groups to form coenzymes

They are used as specific signalling molecules in the cell

Cellular growth and activity (transcription, translation)

Cellular reproduction

what is the central dogma of life?

- Information flows from DNA, which is transcribed into RNA, which is translated into protein

- DNA contains all the information needed to make proteins

- RNA is used as a messenger to carry the information to the ribosomes

- transcription can be reversed but translation cant

what is the structure of a phosphate group?

A phosphor atom bonded to 4 oxygen atoms

what is the structure of epithelial tissue?

• Made of cells which fit tightly together with no gaps

• Cells sit on a basement membrane

what is the function of epithelial tissue?

protection, secretion, absorption, excretion

- form boundaries between body organs and the external environment

what are the two types of epithelial tissues?

- covering and lining (line body surfaces, cavities and lumen)

- glandular (involved in secretion

what are the layers of epithelial tissue?

simple and stratified

what are the shape/function of epithelial tissue - simple?

- squamous (filtration and diffusion)

- columnar (secretion and absorption)

- cuboidal (secretion and absorption)

- can be pseudostratified columnar (secretion) or transitional epithelium

what are the shape/function of epithelial tissue - stratified?

- squamous (protection)

- columnar (secretion and protection)

- cuboidal (protection)

- transitional epithelium (allows disintention)

what are the locations of simple epithelial tissue?

- squamous: alveoli, lining of heart, blood vessels

- cuboidal: kidney tubules, thyroid, pancreas

- columnar (nonciliated): GI tract

- columnar (ciliated): bronchioles, fallopian tubes

- pseudo-stratified columnar: trachea, bronchi

what are proteoglycans a main component of?

the extracellular matrix

are saturated fats solid or liquid at room temp?

solid

what are the locations of stratified epithelial tissue?

- squamous: mouth, oesophagus, vagina, skin

- cuboidal: ducts of sweat glands, male urethra

- columnar: urethra, oesophageal glands, conjunctiva of the eye

- transitional: urinary bladder, ureter and urethra

what is the cellular arrangement of glandular epithelium

unicellular or multicellualr

types of glandular epithelium

exocrine and endocrine

classification of multicellular glands

by structure (unbranched/simple or branched/complex) and type of secretion (tube shaped/tubular, rounded/acinar/alveolar or tube and rounded/tubuloacinar

epithelial membrane vs synovial membrane

ep: has epithelial membrane and an underlying connective tissue layer

syn: connective tissue layer only

structure of muscle tissue

function of muscle tissue

- contributes to homeostasis by producing movements/heat

skeletal vs smooth vs cardiac muscle tissue

- skeletal: attached to bone

- smooth: muscle layers in hollow organs

- cardiac: muscle of the heart wall

smooth muscle cell shape, nuclei and sarcoplasm

- tapered shape, no branching

- single oval nucleus, centrally located

- sarcoplasm not striated (no orderly arrangement)

skeletal muscle cell shape, nuclei and sarcoplasm

- elongated shape, no branching

- multinucleated (peripheral nuclei just beneath sarcolemma)

- sarcoplasm striated (filaments in orderly arrangement)

cardiac muscle cell shape, nuclei and sarcoplasm

- elongated shape, branching

- single, central nucleus

- sarcoplasm is striated

- intercalated discs between cells/fibres

cardiac muscle structure

- elongated shape

- shorter than skeletal muscle fibres

- branching

- abundant sarcoplams

what are the properties of musclular tissue?

electrical excitability, contractility, extensibility, elasticity

what are the basic functions of nervous tissue

sensory input, integration, control of muscles and glands, homeostasis, and mental activity

what is the structure of nervous tissue?

nerves and neuroglia

what is the general structure of connective tissue?

has two basic elements (cells and EXM - protein fibres and ground substance)

what is the role of ground substance?

- supports cells and binds them together

- contains a range of large organic molecules

- primarily composed of water

- provides a medium for exchange of substances between blood and cells

what is ground substance composed of?

- ground substance: amorphous, can be fluid, semifluid, gelatinous or calcified

- fibres: collagen, elastic por reticular

immature vs mature cells in connective tissue?

immature = blasts (secrete EXM)

mature = cytes (maintain the matrix)

what is the general function of connective tissue

binds, suppoirts and strengthens other body tissues