Module 1: Foundations in biology

Water?

60% of the water we take in= drinking , 30% from food, 10% is metabolic water (a byproduct of respiration).

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Water as a Solvent?

made up of hydrogen ion and hydroxyl ions, Water molecules are charged (oxygen atom being slightly negative and the hydrogen atoms being slightly positive), opposite charges attract= hydrogen bonds (bind water molecules loosely together)

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Water Can Resist Changes in Temperature?

water has a high specific heat capacity - it takes a lot of energy to heat it up, water does not change temperature very easily=useful for living organisms , good habitat= water stable, Water inside organisms is also fairly stable-maintain body tempt

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Strong cohesion between water molecules?

“stick together”, Water molecules=very cohesive=they are polar hydrogen bonds, strong cohesion helps water to flow- useful for transporting substances, gives the water a high surface tension allowing small organisms“walk” on the surface ponds(skaters

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Density and freezing properties?

less dense than its liquid, below 4°C density of water decreases, Ice floats on water and insulates the water below it, Changes in density of water with temperature set up ocean currents, which circulate nutrients.

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Photosynthesis?

Water is used in photosynthesis, so it is responsible for the production of glucose, used in synthesis of many chemicals

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monomers?

small, identical or similar molecules, joined together to make larger molecules called polymers.

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polymers?

large molecules which are formed by joining many identical or very similar monomers together.

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examples of monomers?

Nucleic acids, amino acids, α&β glucose, fructose, fatty acids and glycerol

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which x3 components is a nucleotide made up of?

1. A nitrogenous base 2. A pentose sugar 3. One or more phosphate groups

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What are the x2 types of pentose sugar are found in nucleotides

Deoxyribose (found in DNA) and ribose (found in RNA).

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Glucose?

hexose sugar (a monosaccharide), six carbon atoms in each molecule, x2 types= alpha (α) and beta (β), They are isomers.

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List x2 other monomers ?

fructose + animo acid

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Definition of 'isomers'?

have the same molecular formula, but the atoms are connected in a different way.

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x3 key polymers to learn?

Carbohydrates: monomers joined by glycosidic bonds. Proteins: Monomers joined by peptide bonds, Lipids: Monomers joined by ester bonds

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Peptide bond?

formation is a dehydration synthesis reaction, carboxyl group of one amino acid is linked to the amino group of the incoming amino acid, in this process a molecule of water is released.

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Ester bond?

Triacylglycerol is formed with an ester bond by the joining of three fatty acids to a glycerol backbone in a dehydration reaction, three molecules of water are released in this process.

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Types of reactions in biological molecules?

Dehydration (condensation) + Hydrolysis.

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What elements do Carbohydrates contain?

carbon, hydrogen and oxygen= provide energy to the body, particularly through glucose - a simple sugar.

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Formula of Carbohydrates?

(CH2O)n n is the number of carbons in the molecule

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How are Disaccharides formed?

two monosaccharides are joined together by a glycosidic bond- condensation reaction (removal of a molecule of water)

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x3 common disaccharides?

Sucrose (glucose + fructose), lactose (glucose + galactose), maltose (glucose + glucose).

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Polysaccharides?

A long chain of monosaccharides that are linked by glycosidic bonds (i.e- Cellulose, starch and glycogen)

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structure of cellulose?

a polymer of β glucose - it’s made of long, unbranched chains of beta-glucose, Condensation reaction (link carbon 1 to carbon 4 on next β glucose), glucose subunits in the chain are oriented alternately upwards+downwards, position of straight line.

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How are cellulose chains linked together?

by hydrogen bonds to form strong fibres called cellulose microfibrils.

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What do cellulose microfibrils help bring?

structural support for the cells (e.g. the cell walls) + prevents plant cells from bursting - even under very high (water) pressure.

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Amylose?

long, unbranched chain of α-glucose. The angle of the glycosidic bonds give it a coiled, cylinder-like structure, compact structure (good for storage)

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Amylopectin?

long, branched chain of α-glucose, side branches which allow the enzymes that break the molecule down to access glycosidic bonds easily - meaning the glucose can be released quickly.

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Lipids?

a mixed group of hydrophobic compounds composed of the elements carbon, hydrogen and oxygen

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What are the main complex lipid types?

triglycerides + phospholipids.

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Hydrophobic?

water fearing, non-polar molecules, lipid soluble.

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Hydrophilic?

water loving, polar molecules, water soluble (not soluble in lipids).

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What is a 'Glycerol'?

ssmall, 3-carbon molecule with three alcohol groups. (C3H8O3),

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micelle?

circle

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bilayer?

straight

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What's the naturally-occurring structure of phospholipids called?

a liposome

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Proteins?

Amino acids are the monomers that make up proteins.

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How is a polypeptide formed?

via condensation reactions between the amine group of one amino acid and the carboxyl group of another. (water of molecule released

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peptide bonds?

bonds formed between amino acids

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How is the sequence of amino acids in a polypeptide determined?

by the sequence of the genetic code on mRNA being translated in the ribosomes.

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What are the x4 levels of protein structure?

Primary, secondary, tertiary and quaternary

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Primary Structure?

unique sequence of amino acids in the polypeptide chain is its primary structure

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Secondary Structure?

result of protein folding,held together by hydrogen bonds between the carboxyl groups + the amino groups in the polypeptide backbone, most common secondary structure motifs= α-helix and the β-pleated sheet

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How is the α-helix is held together in the secondary structure?

held together by hydrogen bonds running parallel with the long helical axis. There are so many hydrogen bonds that this is a very stable and strong structure.

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Tertiary Structure?

held together by bonds between the R groups of the amino acids in the protein (depends on the sequence of a.a in protein), x3 kinds of bonds involved:Hydrogen, Ionic bonds, Sulphur bridges.

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What are the x3 bonds involved in the Tertiary structure?

1). Hydrogen bonds: which are weak. 2). Ionic bonds:between R-groups with positive or negative charges, which are quite strong. 3). Sulphur bridges:covalent S-S bonds between two cysteine amino acids, which are strong.

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Quaternary Structure?

proteins that are formed from several polypeptides, also known as subunits, and the interaction of these subunits forms the quaternary structure.

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List x3 examples of a Quaternary Structure?

1). Collagen:a fibrous protein of three polypeptides(trimetric)that are supercoiled like a rope. 2) Hemoglobin-a globular protein with four polypeptide chains (tetrameric) 3). Insulin - two polypeptide chains (dimeric) held together by disulfide bond

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basic structure of a nucleotide?

1. A pentose sugar (made with 5 carbon atoms) 2. A nitrogenous base 3. A phosphate group

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What's a polynucleotide?

a polymer of nucleotides, (Both DNA and RNA form polynucleotides),

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How are nucleotides joined?

condensation reaction between the phosphate group of x1 nucleotide and the sugar of another=forms strong,covalent,phosphodiester bond(consists of the phosphate group and two ester bonds)-chain of sugars+phosphates known as the sugar-phosphate backbon

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what occurs when a polynucleotide is formed?

the 5′ phosphate of the incoming nucleotide attaches to the 3′ hydroxyl group at the end of the growing chain.

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Definition of semi-conservative replication?

half the strands in each new DNA molecule come from the original DNA molecule. (ensures genetic continuity between generations of cells)

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What does 'degenerate' mean?

genetic code is degenerate.= more possible combinations of codons are present than number of amino acids,ome amino acids are coded by more than one codon, e.g. tyrosine can be coded for by UAU or UAC.

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What are the x3 main processes in gene expression?

1). Transcription (The conversion of DNA to mRNA with the help of RNA polymerase and transcriptional factors) 2). Post-transcriptional Modifications 3). Translation (Conversion of mature RNA into protein)

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Structure of RNA?

1). ribonucleic acid 2). single stranded and have uracil as base instead of thymine present in DNA 3). formed from ribose sugar, bases + phosphates.4). various types of RNA: mRNA, tRNA, rRNA

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Messenger RNA (mRNA)?

1). made during transcription from DNA. 2). It has single polynucleotide strand. 3). Three adjacent bases form a group in mRNA, known as codons or triplets.

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Transfer RNA (tRNA)?

1). involved in translation. 2). single polynucleotide stranded but bends 3). shape maintained by the hydrogen bonds between specific base pairs (anticodon, recognises the codon on mRNA)

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Transcription?

first stage of protein synthesis.

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Translation?

second phase of protein synthesis.takes place in cytoplasm with the help of ribosomes both in prokaryotes and eukaryotes.

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Role of Ribosomes?

The two units of ribosome joined to form a cleft like structure where mRNA attaches itself. Also it moves along the length of mRNA facilitating the base pairing of mRNA and tRNA.

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Role of tRNA?

two roles: 1). base pairs with codons of mRNA complementarily with its anticodon. 2). Also it carries amino acids specific to the codons on mRNA.

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Role of ATP?

It provides energy for the bond formation between tRNA and amino acid.

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Enzymes?

biological catalysts,

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Hydrolases?

enzymes which help in splitting up of a molecule by adding water and the process is hydrolysis

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Examples of Hydrolases?

tive enzymes like amylase, lipase, protease etc.

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x5 Functions of Cell Membrane?

1. Separation between the extracellular fluid and the internal components of the cell. 2. Communication with other cells. 3. Recognition of external substances. 4. Structural support. 5. Transport of materials.

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mechanisms of the transport of materials?

● Simple diffusion. ● Facilitated diffusion. ● Osmosis. ● Active Transport. ● Co-transport.

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Mitosis ?

ell division which produces two daughter cells that are identical from the parent cell.

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Meiosis?

cell division which produces daughter cells that is not identical to the parent cell, and contains half the amount genetic material as the parent cell.

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Stem cells?

Different cell types, each having a specialised function, make up the multicellular organisms, unspecialised.

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Examples of Stem cells?

muscle cells, liver cells, WBC, RBC

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Cell Differentiation?

The division of stem cells

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Neutrophil- Specialised cells?

1. phagocytic cell that is attracted via chemical messenger from the bloodstream to infected tissues. 2. primary pathogen-killing cell of the inflammatory process of the innate immune response.

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Epithelial cells-Specialised cells?

1.cells forming the outermost layer on the surfaces of organs.2. have a membrane at their base and joined by interlinking cell membranes.

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Ciliated epithelia?

cilia to brush away the particles

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Squamous epithelia?

extremely thin, which allows diffusion of gases in a smooth manner.

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Sperm cells?

1. Flagella help these to swim towards the egg (female sex cell) 2. mitochondria supplies the required energy

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Palisade cells- Specialised cells ?

1. main site for photosynthesis on a leaf surface 2. ontain the most number of chloroplasts 3. absorb a lot of sunlight and let the carbon dioxide easily diffuse into the active site for photosynthesis.

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Root hair cells- Specialised cells?

1. designed to absorb water and minerals from the soil 2. thin and permeable cell wall 3. large surface area allows the inflow of water and necessary ions. 4. Extra mitochondria in cytoplasm to provide the extra energy for the process of absorption

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Module 1: Foundations in biology

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