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.