Biology 1-3 Flashcards
What are the seven processes that living things are required todo to sustain life.
– Movement – Sensitivity – Growth – Reproduction – Excretion – Nutrition – Respiration
Describe what movement is?
Living things can control and direct where and when they move. For example, plant cells can orientate towards the light (phototropism).
Describe what sensitivity is?
Living things can detect and response to changes in their environment. For example changes in sound, light or smell.
Describe what reproduction is?
In Mitosis, cells can divide to form identical daughter cells which allows cells in tissues to divide for growth and repair. For this process to occur Genetic information in the nucleus is duplicate.
Describe what is growth is?
Increase in size, maturity and complexity.
Describe what is nutrition is?
Nutrients provide the raw materials for energy to fuel processes such as growth and repair.
Describe what excretion is?
Chemical processes create toxic waste which must be excreted (got rid of) by the body.
Describe what respiration is?
CELLULAR RESPIRATION is the process of OXIDIZING organic food molecules (e.g glucose) to CARBON DIOXIDE and WATER.
What are the levels of organisation?
Chemical Components< Cell Components< Cells < Tissues < Organs < Organ System < Organism
Why does carbon make up all living things?
Can make 4 bonds.
Carbon can also bond to other atoms and chemical groups.
What does tetravalent mean?
The element can make 4 covalent bonds.
What properties account for the diversity and stability of carbon- containing compounds and its role in biological molecules?
Valence and Low atomic weight.
Functional groups can be classes as hydrophobic or hydrophilic depending on what?
Charge and polarity.
What is a macromolecule?
LARGE BIOLOGICAL MOLECULE with REPEATING SUBUNITS and many functional groups. For example: • Carbohydrates • Lipids • Proteins • Nucleic Acid
What are monomers?
REPEATING UNITS which are joined together by COVALENT BONDS to form LONG CHAINS known as POLYMERS.
What reactions are polymers formed by?
Does the reaction require energy?
Polymers are formed by DEHYDRATION synthesis/ reactions. This reaction REQUIRES ENERGY in the form of ATP.
What is a dehydration reaction?
In the reaction a molecule of WATER is formed and REMOVED from the reactants.
What is the name of the reaction in which polymers are broken down by?
What happens in this reaction?
Hydrolysis.
In this reaction ENERGY is RELASED from the bond and is STORED as ATP.
In the reaction bonds between reactants are broken with the ADDITION of a molecule of WATER.
What does a hydrolysis reaction require?
What is it?
Enzyme- An enzyme is a BIOLOGICAL CATALYST that INCREASES the RATE of CHEMICAL REACTIONS without being used up.
What is the composition of a biological molecule?
70% Water
30%- Chemicals
4% Ions, small molecules 2% phospholipids 1% DNA 8% RNA 15% Proteins 2% Polysaccharides
What percentage is water of fresh mass of living organisms?
60%-95%
Water plays a major role in what processes?
GROWTH and REPRODUCTION
HYDRATION
NURTITION,
HYGIENE and HEALTH.
What percentage are body tissues water?
How much water should you drink a day?
How is dehydration treated?
62%
1.5 L
Fluid replacement theory- oral or IV.
What is Capillary refill time?
The way to measure if someone is dehydrated by applying pressure to a capillary bed causing blanching and measuring time taken for the colour to return to normal. (2 seconds adults/ 4 infants.)
How does water aid the movement of chemicals?
Diffusion
Water is a lubricant and regulates body temperature, why are these two properties important?
LUBRICANT in joints and on tissues as well as moistening epithelia surfaces e.g., eye. Water is also a SHOCK ABSORBER in places like the brain.
Water REGULATES BODY TEMPERATURE. Water requires heat to turn to vapour, so when you are hot sweat absorbs the heat from the skin and turns to vapour and evaporates.
What is the structure of water?
Water is a SIMPLE MOLECULE- 1 oxygen atom bonded by a SINGLE COVALENT bonds to two hydrogen atoms.
Why is water a polar molecule?
Water is a POLAR MOLECULE because oxygen has 6 protons in its nuclear so has a stronger nuclear charge whereas hydrogen only has 1 electron in its nucleus so has a weaker nuclear charge. Therefore OXYGEN PULLS the ELECTRONS in the COVALENT BOND towards itself which makes the OXYGEN slightly NEGATIVE and HYDROGEN slightly POSITVE.
What bonding is there within Water?
Describe this type of bonding?
Hydrogen Bonding
Hydrogen bonding is where the slightly positive hydrogen atom is attracted to a near slightly negative oxygen atom on a nearby water molecule which results in the formation of a HYDROGEN BOND.
Why is water a liquid?
HYDROGEN BONDS are WEAK (5-10% strength of a covalent bond) so bonds can easily be broken, which allows molecules to constantly be changing/ forming bonds with other molecules.
Why is water a powerful solvent? Describe using the example NaCl.
Water is a POWERFUL SOLVENT- for example dissolving NaCl. The slightly positive hydrogen atoms are attracted to the Cl- ions and the slightly negative oxygen atoms are attracted to the Na+ ion, so the lattice is pulled apart.
All POLAR MOLECULES and IONS are water soluble because they can form HYDROGEN BONDS with water. Therefore ions/ polar molecules can move freely as well as taking part in cellular chemical reactions.
What is HYDROPHILLIC molecule?
Polar Molecules attracts towards water molecules.
What is HYDROPHOBIC molecule?
Non- polar molecules REPEL water molecules
What is amphiphilic?
Complex molecules have a mixture of both properties.
What is surface tension?
Describe what is surface tension.
SURFACE TENSION is defined as tension of the surface film of a liquid caused by the attraction of the particles in the surface layer so as to reduce surface area.
At liquid–air interfaces, there is a STRONGER attraction between water molecules via hydrogen bonding than water to air molecules. A certain amount of energy is required to break the hydrogen bonding and break the surface tension.
What is a surfactant?
AMPHILLIC SUBSTANCES which reduce the surface tension of a liquid which they are dissolved in, e.g. emulsifier.
What does a surfactant do. Use the example of a surface with soil on.
For example, the hydrophobic tails are attracted to soils and surround them, while the hydrophilic heads pull the surrounded soils off the surface and into the cleaning solution.
What are Carbohydrates?
BILOGICAL MOLECULES containing HYDROGEN, OXYGEN and CARBON.
What is a carbohydrates empirical formula?
Cm(H2O)n
What are carbohydrates known as?
‘saccharides’
What are the functions of carbohydrates?
Provide a RAPID and readily available supply of ENERGY for cellular reactions e.g. Muscle & liver glycogen
FORM part of important MOLECULES in the cell e.g. Sugar-phosphate backbones in DNA double helix.
FORM MARKERS on the cell surface which aid cell recognition e.g. Blood group markers.
What is a monosaccharide?
A MONOMER and has the general formula (CH2O)n.
What is a disaccharide?
2 MONOSACCHARIDES.
What is an oligosaccharide?
POLYMER of 3-20 MONOSACCHARIDES.
What is a polysaccharide?
POLYMER of MONOSACCHARIDE units linked together.
Name some examples of monosaccharides.
GLUCOSE, RIBOSE and FRUCTOSE.
What type of molecules of monosaccharides?
Single sugar molecules.
What does a monosaccharides
molecule contain.
Range from 3-10 carbons.
Aldehyde or Ketone group
and a Hydroxyl group.
What are the names of 3-10 carbon molecules.
Three carbons – triose Four carbons – tetrose Five carbons – pentose Six carbons – hexose Seven carbons – heptose Eight carbons – octose Nine carbons – nonose Ten carbons – decose
How to name a monosaccharides?
Count Carbons from the aldehyde/ ketone which is considered the top.
What does it mean if the molecule is in the ‘Deoxy form?’
How do you name a deoxy form in a molecule?
Where the hydroxyl group is replaced with a H.
The carbon which is in the deoxy form is number _- deoxy- MOLECULE NAME.
What are stereoisomers?
STEROISOMERS have the same chemical formula and order and types of bonds but there are non- overlapping mirror images and so have different special arrangements and biological functions.
What is the requirement for a stereoisomer?
Chiral Carbon- A CHICAL CARBON has 4 different groups attached to it.
How do you know if a molecule is an L or D stereoisomer?
Using the Fisher projection if the OH on the bottom chiral centre points to the RIGHT is the D isomer and if the OH on the bottom chiral centre points to the LEFT is the L isomer.
What is cyclization?
CYCLIZATION is when the OH group on the second to last carbon reacts with carbonyl group. Resulting product from an aldose is a HEMIACETAL and a resulting product for a ketose is a HEMIKETAL.
Under normal conditions, what happens to monosaccharides?
Monosaccharides cyclize spontaneously under normal conditions with only small amounts of the straight chain present.
What is the cyclic form of D-glucose called?
Why are there 2 possible hemiacetal products of D-glucose? What are there names?
D-GLUCOPYRANOSE
The C=O group is planar so the OH group can attack from either side so there are 2 possible hemiacetal products which are A and B ANOMERS of D-glucopyranose.
Why is glucose the primary energy source for life?
SEVEN energy-rich C-H bond. The bonds are broken down during CELLULAR RESPIRATION and released energy is stored as ATP for use by the cell.
What is the importance of fructose?
Where is fructose found?
In cyclization- what does fructose form? Why is this unusual?
FRUCTOSE has SEVEN energy-rich C-H bond. It is an important source of energy, along with glucose and galactose.
Fruits, honey, berries and melons.
Fructose forms a FURAN-BASED ring structure, 5 membered cyclization product, despite being a hexose, 6 carbon.
Name some examples of disaccharides?
SUCROSE, MALTOSE and LACTOSE.
How are disaccharides formed?
What is the reaction aided by?
What bond is formed?
Formed by DEHYDRATION synthesis, condensation reaction, with the loss of H2O molecule. The reaction is aided by ENZYMES, biological catalysts. Monosaccharides are joined at –OH groups by GLYCOSDIC BOND.
What is the primary function of a disaccharide?
The primary function of a disaccharides is a NURTITIONAL SOURCE of monosaccharides.
What is Maltose?
Where is the OH group on the Maltose?
MALTOSE is when TWO GLUCOSE molecules join at carbons 1 and 4 via an
a-1,4 glyosidic link which is where the OH group on the Carbon 1 is BELOW the plane of the glucose ring.
What enzyme hydrolyses maltose in to glucose?
Maltase
How is maltose generated?
Breakdown of Starch.
What is a condensation reaction?
A CONDENSATION REACTION is when 2 molecules combine to form a larger molecule with the loss of a small molecule, e.g. H2O.
What is a hydrolysis reaction?
A HYDROLYSIS REACTION is the cleavage of chemical bonds by the addition of water. A disacharide can be broken down to its constitute monosaccharide with H2O and its specific enxyme.
What is lactose?
Where is the OH on Carbon 1 in lactose?
LACTOSE is when GLUCOSE and GALACTOSE molecules join at carbons 1 and 4 via a
b-1,4 glyosidic link which is where the OH group on the Carbon 1 is ABOVE the plane of the glucose ring.
How is lactose produced?
Lactating mammals as an energy source for their young
Lactose is digested into _________________
Glucose and Galactose
What enzyme hydrolyses lactose in to glucose and galactose?
Lactase
What is sucrose?
Where are molecules joined together?
SUCROSE is when GLUCOSE and FRUCTOSE molecules joined at carbons 1 and 2 via an a-1,2 glyosidic link.
Where is sucrose found?
Sap of Sugar Cane
What enzyme hydrolyses sucrose in to glucose and fructose?
Sucrase
What do organisms convert soluble sugars into an insoluble form?
– For storage in the cell (e.g. starch, glycogen)
– For building structures (e.g. cellulose in plant cell walls)
– For taking part in cellular processes (e.g. generation of glucose for energy)
How are OLIGOSACCHARIDES and POLYSACCHARIDES created from monomers?
CONDENSATION REACTIONS.
Give an example of a POLYSACCHARIDES
STARCH
What does starch consist of?
AMYLOSE and AMYLOPECTIN.
What is AMYLOSE?
Long linear chains of α-1,4-linked-D-glucose that has a coiled structure.
What is AMYLOPECTIN?
Linear chains of a-1,4-linked D-glucose joined through a-1,6-linked branch points
Name 2 functions of starch?
Where is starch found?
Main SOURCE of carbohydrates
Main STORAGE polymer in plants.
AMYLOPLASTS and CHLOROPLASTS
What are AMYLOPLASTS?
AMYLOPLASTS are non-pigmented plant cell organelles which are responsible for synthesis and storage of starch granules through polymerization of glucose.
How is starch broken down?
What is starch digested into?
A-1,4 glycosidic links are broken down by AMYLASE (saliva and gut) and MALTASE (gut only), whereas ISOMALTASE (gut only) break down a-1,6 glycosidic links.
Starch is digested into dextrins, maltotriose, maltose, isomaltose and ultimately glucose
What is glycogen?
GLYCOGEN is a complex branched polysaccharide of linear chains of a- 1,4-linked D-glucose joined through a-1,6-linked branch points.
What structure is glycogen similar to? How?
Glycogen structure is similar to amylopectin but branch points occur more frequently, every 8-12 instead of 24-30 in amylopectin.
What are the 2 function of glycogen?
Where is glycogen found?
The main STORAGE polymer of ANIMALS.
Readily hydrolysed to GLUCOSE when energy is required.
In liver and muscle cells
What enzyme is involved in converting glucose into glycogen?
GLYCOGENIN
What are glycoproteins?
GLYCOPROTEINS are PROTEINS that contain OLIGOSACCHARIDE chains attached COVANTLY to the protein structure.
What are the functions of glycoproteins?
Plays an important role in immune recognition. Secreted glycoproteins make up mucins, principal component of mucus and the glycocalyx.
What is the glycocalyx?
Glycoprotein covering surrounding cell membranes of epithelial cells.
What are GLYCOLIPIDS?
GLYCOLIPIDS are LIPIDS that contain OLIGOSACCHARIDE chains attached OLIGOSACCHARIDE to their lipid structure.
What are the functions of GLYCOLIPIDS?
Recognition signals, attachment factors and membrane stabilisers.
What are SPHLINGOLIPIDS? Give examples of SPHLINGOLIPIDS.
Sub type of lipids which include CERAMIDE, signalling molecule and SPHINGOMYELIN, membranes.
What are GLYCOSPHINGOLIPIDS? Give examples of GLYCOSPHINGOLIPIDS.
subtype of sphingolipids which are found in CEREBROSIDES which are found in muscles and nerves and GANGLIOSIDES found in plasma membranes.
