Wednesday, November 30, 2011

2.8a Enzymes

2.8 understand the role of enzymes as biological catalysts in metabolic reactions

28a Enzymes

1. Catalyst = makes the reaction occur faster under moderate conditions. 
2. Metabolical reactions = biological reactions taking place in a cell, building molecules up or breaking them down. 
3. Lock and Key Hypothesis 
Enzymes have a particular shape 
Enzymes are 

a)  Enzyme

b) Active site - where the substrate (c) fits in. Called: COMPLEMENTARY 
(d) Activated Complex (substrate in active site)
(e) Products emerge from the enzyme (substrate has been broken down into two products) - (f)

Enzyme remains unchanged

Substrate -----> Product 

2.7 Lab Tests for glucose and starch

2.7 describe the tests for glucose and starch

1. Glucose (C6 H12 O6) positive test 
a) Take glucose powder and dissolve it in a test tube 
b) Add  Benedict's Reagent (blue) 
c) Take test tube and place in a water bath to boil (60-70C) for 2-3 minutes
d) Remove test tube
Result = colour change from blue to orange.

2. Starch positive test 
a) In solid form = white powder
b) Place some white powder into a spotting tile 
c) Add Iodine Solution (brown)
Result = colour change from brown to dark blue/black colour

2.6 Biological Molecules Structure

2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar; protein from amino acids; lipid from fatty acids and glycerol

1. Carbohydrates (CHO) ---> Sugars (glucose) combine to form STARCH (plants) and GLYCOGEN (animals)

2. Proteins (CHON) ---> Amino Acids join together in long chains which join together to make proteins.
Broken down they form smaller molecules (the amino acids)

3. Lipids (CHO) ---> (have 2 different kind of molecules) --> Glycerol + Fatty acids which join together to form Lipids.

2.5 Elements in biological molecules

2.5 recall the chemical elements present in carbohydrates, proteins and lipids (fats and oils)

1. Carbohydrates --> Carbon, Hydrogen, and Oxygen ---> Sugars + Polysaccharides (starch)
2. Proteins           ---> Carbon, Hydrogen, Oxygen, and Nitrogen ---> Amino Acids + Proteins
3. Lipids              ----> 
Carbon, Hydrogen, and Oxygen ----> Fats (animals) and Oil (plants) 

Tuesday, November 29, 2011

2.4 Differences between Plant and Animal cell

2.4 describe the differences between plant and animal cells.

Animal Cell: 
Cell membrane

Shape: Rounded
Store: Glycogen molecule (carbohydrate)

Plant Cell:
Cell MembraneNucleusCytoplasm
Cell wall
Shape: regular shape
Central Vacuole
Store: Starch molecule (carbohydrate)

Functions of parts of a call

1. Plant Cell 
Vacuole = Stores molecules (amino acids, sugars etc)
Chloroplasts = Where photosynthesis occurs
Cell wall = Provides the protection and support for the cell. 
2. Animal cell

Cell Membrane = controls what goes and leaves the cell
Nucleus = Controls what the cell does
Cytoplasm = where chemical reactions take place eg: respiration.

Sunday, November 27, 2011

2.2 Cell structure

Recognize cell structures, including the nucleus, cytoplasm, cell membrane, cell wall chloroplast and vacuole.  
N = nucleus
CM = Cell membrane
C= Cytoplasm
V= Vacuole
CW= Cell wall

Sunday, November 20, 2011

2.1 Levels of Organisation

2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems.
example suing Plant.
1. System: Composed of a group of organs  working together on eg: Plant cell; Reproduction, Photosynthesis, Transport.

2.  Organ:  Group of different Tissues working together.
Leaf: 3 different Functions: Photosynthesis, Gas Exchange and Transpiration.

3. Tissue - Group of cells of the same kind = they have the same shape and function.
eg: Phloem - Cell that transports "sap"
eg: Xylem - Transports water and minerals.
eg: Plaside - Carries out P/S

4. Cells: multicelluler organinisum.
a) In development of the organism, the cell specializes: they switch on genes which change their shape giving the cell a particular function: This is called  Cells differentiation 

Monday, November 7, 2011

2.75 Urine

Recall that urine contains water, urea and salts 

1. Brain influences the the functioning of the kidneys
2. Kidneys filter out blood
3. Molecules removed come out the ureter and collect in the bladder as urine
4. Urine contains salt, water and urea --- which affects the composition of the tissue fluid = Osmoregulation
5. Removal of urea = excretion of metabolic waste.
- composition of salt, water and urea varies and depend upon conditions in which a person is operating.

Sunday, November 6, 2011

2.74 ADH.

Describe the role of ADH in regulating the water content of the blood. 

1. ADH (anti - directic hormone) is produced in the brain - located in the Hypothalamus region of the brain. ADH flows through the blood stream and targets the kidneys.

2. Function of ADH: to control and alter the quantity/composition in the blood. - Making it more or less concentrated.

3. ADH targets --> collecting duct

Affect: allows more water to come out of the collecting duct. (collecting duct = where water is selectivly reabsorbed into the blood) - ADH increases the quantity of the water being removed.

4. ADH secretion = more water goes back into the blood, urine becomes more concentrated and the volume decreases. 

2.73 Glucose reabsorption

Understand that selective reabsorption of glucose occurs at the proximal convoluted tubule. 

1. Selective reabsorption = molecule is selected --> (glucose)
    reabsorption - glucose will go from the Glomeral filtrate and then go back into the blood

2. Filtration occurs in the Bowmans Capsule - The filtrate containing glucose, water, salts and urea (formed from the high pressure of blood) - Water is removed back into the blood in the collecting duct

3. Urine coming out of the Nephron - does not contain glucose. (if glucose is present in urine this is an indication of a condition called Diabetise).

4. Glucose is in the fluid in the first Proximal (1st) Convoluted (twisted) tubule - glucose is removed here and taken back into the blood.

5. Glucose is selectively reabsorbed into the blood in the Proximal Convoluted Tubule (no glucose in Urine)

2.72 Water re-absorption.

Understand that water is reabsorbed into the blood from the collecting duct. 

1. Bowman's capsule: where ultra filtration occurs.

a)Blood goes into the kidney at high pressure
b)The dissolved contents of the blood are forced into the Bowman's capsule (Glomerula filtrate) --> glucose, water, salt, and urea. 
c) When filtration occurs, too much water is filtrated. The filtrate passes along the tubule and when it reaches the collecting duct and passes through - water is removed from the filtrate as it goes down the medula. The water is then returned back into the blood vessels.
d) Water has been selected - and reabsorbed into the blood.

2.71 Ultrafiltration

Describe ultrafiltration in the Bowman's capsule and the composition of the glomerular filtrate. 

1. Nephron - carries out the filtration of blood --> filtered blood (clean)
                                                                            --> Urine (waste)
2. Urine is composed of: Water, Salts, and Urea (nitrogen waste - toxic) 

3. Bowman's Capsule: where ultra-filtration begins.
a) Blood arrives in the kidney in the Afferent arteriole - at high pressure - (with a wide blood vessel).
b) Blood passes through the Glomerulus and pases out the Efferent arteriole - (with a narrow blood vessel.)
c) Blood pressure increases in the Glomerulus.
d) High pressure forces the plasma (liquid in blood - water, salts, amino acids, glucose and urea) out of the blood vessel into the inside of the Bowman's Capsule - This is called "Glomerula Filtrate."

2.70 Nephron Structure

Describe the structure of a Nephron to include Bowman's Capsule and glomerulus, convoluted tubules, loop of HenlĂ© and collecting duct. 

  1. Renal Vein
.Carries blood away from the kidney and back to the right hand side of the heart. Blood in the kidney has had all its urea removed. (Urea is produced by your liver to get rid of excess amino-acids).
Blood in the renal vein also has exactly the right amount of water and salts. This is because the kidney gets rid of excess water and salts. The kidney is controlled by the brain. A hormone in our blood called  ADH  is used to control exactly how much water is excreted.

  1. Renal Artery
This blood vessel supplies blood to the kidney from the left hand side of the heart. This blood must contain glucose and oxygen. Blood in the renal artery must have pressure to be able to filter the blood.
Blood supplied to the kidney contains a toxic product called urea which must be removed from the blood. It may have too much salt and too much water. (The kidney removes these excess materials)

  1. Pelvis
This is the region of the kidney where urine collects. 

  1. Ureter
The ureter carries the urine down to the bladder and is stored there until excreted.
 E.     Medulla
The medulla is the inside part of the kidney (green) (real life: dark red) This is where the amount of salt and water in your urine is controlled. It consists of billions of loops of Henlé. ADH makes the loops work harder to pump more sodium ions. The result of this is that very concentrated urine is produced.

  1. Cortex
The cortex is the outer part of the kidney. This is where blood is filtered. We call this process "ultra-filtration"  because it only works if the blood entering the kidney in the renal artery is at high pressure.
A glomerulus is a tiny ball of capillaries (found in the cortex). Each glomerulus is surrounded by a "Bowman's Capsule". Glomeruli leak. Things like red blood cells, white blood cells, and platelets  stay in the blood vessels. Most of the plasma leaks out into the Bowman's capsules. 
Most of this liquid, which we call "ultra-filtrate" is re-absorbed in the medulla and put back into the blood.