Energy is not created or destroyed, it is transformed
2nd law of thermodynamics
When energy is tranfered, some of it is lost to entropy
Based on the 1st and 2nd laws of thermodynamics, what happens to energy as it is trasfered along the food chain?
Only about 10% of the energy stored in the organic matter of each trophic level is converted to organic matter in the next trophic level.
Maintining the internal milieu constant
Dynamic equilibrium, healthy balance inside body
i.e. body temprerature, blood sugar, pH of blood cells, blood volume
Growh and development is controlled by?
What is cytoplasmic streaming?
The movement of organelles within the cytoplasm
What is a stimulus?
A change in the environment. Can be internal (within an organism) or external
What is asexual reproduction?
+ Examples of asexual reproducers?
One individual producing genetically identical offspring
ex. bacteria, regeneration, cutting off a plant
What is sexual reproduction?
Two individuals contributing an equal amount of genetic information, producing genetically different offspring
ex. animals, pollination of plants
What is unique about the chemical composition of water?
Water is polar covalentPolar covalent = the unequal sharing of electrons within a molecule
Oxygen is electronegative
Hydrogen end is slightly positive
Oxygen end is slightly negative
What is a hydrogen bond?
A bond formed between the hydrogen of a one water molecule and the oxygen of another water molecule. Water molecules bond together with hydrogen bonds.
One molecule can cling to a maximum of 4 other water molecues.
Properties of Water
3) Capillary action
4) Tensile strength
5) High specific heat capacity
6) HIgh heat of vaporization
7) Versatile solvent
What is cohesion?
The clinging of water molecules to other molecules using hydrogen bonds
i.e. water spiders spread their weight over a large surface area so as to not pierce the surface tension of the water
What is adhesion?
Water's strong tendency to cling with hydrophilic molecules
Hydrophilic molecules are polar/charged
Water doesn't cling to hydrophobic molecules (non-polar molecules such as lipids, oil)
What is capillary action?
Tendency of water to go up against gravity within a small diameter tube（vessel)
What is tensile strength?
Water's resitance to being pulled apart due to gravity
Describe water's high specific heat capacity
Requires a lot of energy to increase the temperature of water because hydrogen bonds must be removed
Important for homeostasis of body temperature (keeps temperature constant)
Describe water's hig heat of vaporization
Requires a lot of energy for a molecule of water to turn into vapour
The remaining surface cools-> evaporative cooling, ex. sweating and panting-> homeostasis of body temperature
How does water travel through a plant?
1. Water clings to the soil particles by adhesion2. Water molecules form a chain by cohesion3. Water goes up the root by capillary action, clings to cell wall xylem by adhesion
xylem=tubes in stem of plant4. The chain of water molecules is not broken by gravity due to tensile strength5. Water leaves by transpiration during gas exchangefor photosynthesis, this pulls the chain of water up the plant
What are macromolecules?
Macromolecules are large chaings of organic molecules
Sythesized by cells or obtained from the diet
What are the 4 large classes of macromolecules?
4) Nucleic Acid
What is a monomers called in
c) nucleic acids
b) amino acids
What is a monomer?
A small molecule that usually has a specfic role in the body
Sub-unit of polymers
Contains a hydrogen and hydroxyl end
What is a polymer?
A very large molecule composed of many monomers
What are polymers called in
c) neucleic acids
c) DNA, RNA
How are polymers formed?
Joining of monomers to form larger molecules that eventually become polomers
Process forms water molecules by joining monomers together
How are polymers broken down?
Breaking of large molecules to release monomers usually with the help of a digestive enzyme
Water is absored and the monomer is "hydrolized"
Water is used to BREAK molecules
Give an example of a monosaccharide and list its properties
product of photosynthesis
fuel for cellular respiration
What is a disaccharaide?
Sub-unit formed by two monomers linked with a glycosidic linkage
Give two examples of disaccharides and list their components/properties
Plants transport in phoem
What is a polysaccharide?
They are carbohydrate polymers: composed of many monosaccharides
Polsaccharides store energy and are used as structural/building materials
Name four polysaccharides and list their properties
Composed of many alpha glucose
Storage of energy in plants
Diet complexe carbohydrate
GlycogenComposed of many alpha glucose
Energy storage in liver and skeletal muscles of animals
CelluloseComposed of beta glucose
Cell wall of plant cells
ChitinComposed of amino sugars
Cell wall of fungi (mushrooms, yeast, molds)
Exoskeleton of anthropods (insects, spiders, crustaceans)
Can we digest cellulose?
No, cellulose exits our digestive system in the form of fibers.
Insoluble fibers lower risk of colon cancer
Soluble fibers (oats) lower blood cholesterol
Can we digest Chitin?
Yes, which is why it is used in stitches
True/False: Lipids are hydrophilic molecules
False; lipids are a diverse group of hydrophobic molecules
Name three classes of lipids
1. Fats and oils
What is another name for fats and oils?
Triacylglyceral or tryglycerides
How are fats and oils structured/composed?
Composed of glycerol and 3 fatty acid chains
Bonded with Ester linkages formed through dehydration
Fats and oils: What are two main types of fatty acid chains?
1. Saturated fatty acid chain
2. Unsaturated fatty acid chain
What are the properties of saturated fatty acid chains?
They have no double bonds, all carbons in the chan have two hydrogens
Name some sources of saturated fatty acids and its effects on the human body
Red meat, chocolate, tropical oils
Increases risk of cardiovascular disease
What are the properties of unsaturated fatty acid chains?
They have double bonds and are better for your health
Name two categories of unsaturated fatty acid chains. List their properties, sources and effects on human health
Monounsaturated-One double bond
-Sources: olive oil, canola oil
- Decrease risk of cardiovascular disease and blood cholesterol
Polyunsaturated-Many double bonds
-Decrease cardiovascular diease and symptoms of PMS, menopause
Increase brain integrity
Sources: fish, tuna, salmon, flaxseed
Both hydrophilic and hydrophobic
In a phospholipid: hydrophilic head + two hydrophobic tails
What are phospholipids?
They are a major component of membranes including cell membranes and membrane-bound organelles
Make up the phospholipid bilayer!
What is the group that classifies cholesterol and sex hormones?
Steroids, a sub-category of lipids
What is a precursor and how is this related to cholesterol and steroids?
Cholesterol is made in the liver of animals; it is a steroid used to make other steroids, such as estrogen and testosterone. It is thus named a precursor.
How are lipids transported?
The liver packages them in a lipoprotein for transport
Lipids are wrapped inside a protein
What is "good cholesterol"?
HDL (high density lipoprotein)
Lower blood cholesteral, lower risk of cardiovascular disease