Flashcards
Biochem- outcome 1
Cards in this deck (74)
- 1What are carbohydrates?molecules that function as energy sources or as structural components of cells
- 2General formula for carbohydratesCx(H2O)y
- 3Monosaccharides-single sugar unit
-3 to 7 carbons
-building block for polymers e.g. ribose
- store energy e.g. chemical energy stored in glucose which is released and used to synthesise ATP from ADP+ Pi through cellular respiration - 4Types of Monosaccharides*Glyceraldehyde- important intermediate in cellular respiration & photosynthesis
*Ribose & deoxyribose- structural components of RNA & DNA
*Glucose- main energy source for heterotrophic cells. - 5Structural formula for glucose- linear molecule
- 'ring' structure (when dissolved in water) - 6Linear Glucose2 forms(isomers)
- D form- OH group on C5 projects to the right
- L form- to the left - 7Glucose rings-ABBA(alpha below, beta above)
-In alpha glucose the OH group on C1 is below the plane of the ring
-In beta glucose the OH group on C1 is above the plane of the ring - 8Glucose-made by plants during photosynthesis and is used as an energy source by the plant
-can also be built into a long chain molecule as starch - 9Starch-storage form of glucose
-broken down in digestive tracts of animals to release glucose that is used by the animal as energy for cellular respiration - 10Disaccharides2 sugar units joined by condensation when the OH of one monosaccharide combines with H atom of another
-glycosidic bond formed - 11Types of DisaccharidesSucrose- table sugar, alpha(1-2) linkage between glucose & fructose
Maltose- produced from starch by enzymatic hydrolysis, alpha(1-4) linkage
Cellobiose- subunit of cellulose, beta(1-4) linkage - 12Polysaccharides-made by single sugar units via glycosidic bonds
-structural (cellulose) or storage (starch)
-insoluble in water - 13Starchamylose
amylopectin - 14Forms of Polysaccharides-branched (glycogen)
-unbranched (cellulose)
-coiled (amylose) - 15Homopolymers & Heteropolymers*Homopolymers- same constituent molecules
*Heteropolymers- different constituent molecules - 16Cellulose-component of cell walls
-confers rigidity & support
-made of glucose molecules joined by ß(1-4) glycosidic bonds
- successive glucose units are inverted with respect to one another=> allows H bonding to take place between parallel chains of cellulose-adds to the stability of molecule - 17StarchAmylose: many glucose joined by α!1-4) glycosidic bonds. forms linear chains of α glucose molecules that coil into a helix
Amylopectin: branched chain α glucose . α(1-4) (between molecules) and α(1-6)(brances) glycosidic bonds - 18Glycogen-short term energy store
-highly branched
-composed of many α(1-4) and α(1-6) glycosidic bonds. - 19Reducing SugarsReducing means they are able to reduce Cu2+ ions present in blue Benedict's solution into Cu+, which in the presence of NaOH forms red precipitate
- 20Carbohydrates Test-mono and disaccharides( except sucrose) are reducing sugars
-Starch gives blue/black colour with iodine
-Glycogen stains dark brown
-Cellulose doesn't stain - 21Lipidsare biologically important because they:
-provide long term source of energy
-function as hormones
-are structural components of biological membranes
-provide a layer of insulation in animals
Lipids are oily compounds, insoluble in water, hydrophbic - 22Types of lipids-triglycerides
-phospholipids
-sphingolipids
-glycolipids
-steroids - 23Triglycerides-composed of 3 fatty acids and 1 glycerol molecule
-main function- act as an energy store
-fatty acids can be saturated or unsaturated
-fats(animals) are saturated solid at RT
-oils(plants) are unsaturated at RT - 24Phospholipids-composed of 2 fatty acids and phosphate connected to glycerol
-an amphipathic molecule -->has both hydrophobic and hydrophilic part
- forms phospholipid bilayer --> polar phosphate head is hydrophilic so orientates towards aqueous fluid inside & outside the cell. The hydrophobic tails orientate themselves into position away from water - 25Sphingolipids-derived from alcohol sphingosine
-found in cell membranes forming stable rafts to protect cell surface
-rafts from mechanically stable & chemically resistant outer region of cell membrane - 26GlycolipidsLipids with carbohydrate groups attached
-act as markers for cell for cellular respiration
-act as recognition sites for specific chemicals
-act as receptors
-involved in cell to cell communication
-assist in attachment of cells - 27Steroids-consist of 4 rings of carbon with protruding side chains
-animal hormones, constituent of cell membranes e.g. cholesterol + control the fluidity of the plasma membranes - 28Proteins-essential in biological systems as control and structural elements
-function is determined by their structure
-heteropolymers made up of AA - 29Functions of Proteins-Enzymes
-Structural
-Movement
-Transport
-Protective
-Hormones
-Storage
-Receptors
-Toxins
-Control of gene expression - 30Enzymes-biological catalysts
-involved in biochemical reactions
-increase reaction rates
-specific, bind to substrates
- most water soluble(globular) - 31Structuralmost water insoluble (fibrous) e.g. collagens, elastins, keratins
- 32Movement-cilia, flagellae, microtubules and microfilaments (change shape and move chromosome in cell)
-actin & myosin in muscles - 33Transportproteins that transport substances across biological membranes e.g. oxygen bound to haemoglobin and surface membrane proteins transporting nutrients into cells
- 34Protectiveantibodies and blood clotting proteins (e.g. fibrin)
- 35Hormonesproteins (e.g. insulin)
- 36Storageproteins used to store potential energy, e.g. casein in milk
- 37Receptorsexamples include, for hormones, nerve impulses and light
- 38Toxinsexamples include snake venoms and bacterial toxins
- 39Control of Gene Expression-prokaryote repressors bind to DNA and repress expression of genes
-eukaryote cell histones bind to DNA and silence genes in differentiated cells - 40Amino Acids-determine function & structure of proteins
-contain an amino(NH2) & carboxyl group(COOH)
-at pH 7 AA are ionised to form zwitterions - 41Polypeptide ChainsA covalent peptide bond is formed between between the amino group of one AA and carboxyl group of another, this forms a polypeptide chain
- 42Side or R groups-affect structure & function of AA
-these groups can be polar, non polar, acidic or basic - 43Polar Side groupsPolar AA are hydrophilic because they from a weak hydrogen bond with water.
The R group contains oxygen & nitrogen - 44Non-Polar side groups-Non- polar AA are hydrophobic
-The side chains don't contains O or N so cluster away from water - 45Acidic side groupsAcidic AA have side chains which can donate a proton to another atom (usually N) and so they become strongly hydrophilic
- 46Basic side groupsBasic AA have side chains which can accept a proton and become positively charges and so become hydrophilic
- 47Primary StructurePrimary structure is the sequence of AA in a polypeptide, for example, lysine-glycine-aspartate-cysteine
- 48Secondary StructureSS refers to the formation of coils & sheets within a polypeptide due to H-bonding
-If the polypeptide is coiled it is usually an alpha helix
-if it's a beta sheet, it can be parallel or anti-parallel - 49Tertiary StructureTS refers to the folding of the polypeptide and is usually controlled by different interactions of the R groups:
-van der Waals forces
-ionic interactions
-H bonding
-disulphide bonds
--hydrophobic interactions - 50Van der Waals forces-non-specific weak interactions
-stabilises protein structure - 51Ionic Interactionsbetween 2 close, oppositely charged R groups
- 52Hydrogen Bondsbetween 2 R groups where H is bonded to a strong electronegative O or N or between R group and water
- 53Disulphide Bondscovalent, strong, common in extracellular proteins, also occur between polypeptides
- 54Hydrophobic Interactionsh
- 55Examples of secondary & tertiary proteinsMyoglobin, amylase & lysozymes.
Myoglobin carries O through muscle tissue, whereas amylase & lysozyme are both enzymes.
Amylase hydrolyses starch &lysozyme breaks down one of the components of the bacterial cell wall - 56Quaternary Structureformed form 2 or more polypeptide subunits e.g. haemoglobin
haemoglobin is made of 4 chains of the protein globin, 2 alpha globin & 2 beta globin - 57Types pf Integral membrane proteins-Transport
-Receptors - 58Transport Proteinsmoving materials in & out, through pores or pumps e.g. Na K pump
- 59Receptor Proteins-allows cells to respond to their environment
-helps convey messages from outside to inside of the cell - 60Fibrous Proteins-rope like structure
-structural proteins as they confer support e.g. collagen - 61Types of Fibrous ProteinsElastin, collagen(2 types), keratin, actin & myosin
- 62Globular Proteinsconsists of several polypeptide chains folded together into a roughly spherical shape like a tangled ball of string
- 63Protein SynthesisDNA to mRNA to protein
- 64Structure of DNAconsists of 2 repeating anti-parallel units called nucleotides
Nucleotides- composed of deoxyribose sugar, phosphate, & a base
4 complimentary DNA bases- A,T,G,C - 65What is a phosphoester bond?-strong chemical bond formed between the phosphate group of one nucleotide and the deoxyribose sugar of another
- difficult to break - 66What is the N-glycosidic bondbond linking the deoxyribose sugar and the organic base
- 67What is the bond joining two strands of DNA together?weak hydrogen bonds
- 68RNA-single stranded
-uracil replaces thymine
-ribose sugar instead of deoxyribose - 69Types of RNA-mRNA: provides the template for protein synthesis during translation
-tRNA: it brings amino acids and reads the genetic code during translation
-rRNA: plays a structural and catalytic role during translation - 70What is the genetic code?information present in DNA forms a molecular coded language known as the genetic code
- 71What is the codon?the basic unit of genetic code
- 72Protein Synthesis-Protein synthesis is the process in which cells make proteins
-occurs in two stages: transcription and translation - 73Transcriptionmulti step process where mRNA is formed (transcribed) from one of the DNA strands using RNA nucleotides from the cell's nucleus
(learn steps in detail) - 74Translationribosome attaches to mRNA. tRNA anticodon bonds with the complimentary codon on mRNA. As AA come in line, peptide bonds are formed & protein is formed
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- Year 1 Biochemistry Flashcards on Biochem- outcome 1, created by Hafsa Safi on 08/09/2022.
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