Human Bio test 2

Types of movement across cell membrane

Types of movement across cell membrane

1. Diffusion - simple diffusion + osmosis (passive)
2. Facilitated Diffusion/ Transport - proteins in cell membrane (passive or active)
3. Vesicular Transport - materials moved in membrane bound sacs (active)

Carrier - Facilitated Diffusion

Transported molecules bind to carrier protein, changes shape and moves molecule
passive process
moves from high concentration to low concentration

Carrier - Active transport

Requires ATP as it moves molecules from low concentration to high concentration

Cellular Respiration def

process in living organisms by which carbon-containing compounds are broken down to release energy in from of ATP

Protein main uses

1. Structural function
2. Metabolic functions
3. Oxygen transport
4. Protection
5. Energy source (in emergencies)

Protein - Amino acids

9 essential amino acids - Histidine, Lysine
Peptide - 1 AA
Dipeptide - 2 AA
Polypeptide - 10 or more AA

Macro minerals

Na, Mg, K, Ca, Fe, P, S, Cl
Required in large amounts

Trace minerals

required in small amounts

Minerals - Functions

1. Ca needed in bones and muscles
2. Na + K important in electrolytes
3. Fe needed in haemoglobin
4. P essential in nucleic acid

Stomach

2 - 8 hours
Lined with mucosa layer
Folds in stomach called Rugae
Gastric pit secretes HCL

Stomach - Mechanical

Muscular contractions churn food + mixes with gastric juice
Converted to thick soupy liquid called Chyme

Stomach - Chemical

Pepsinogen is secreted from gastric pit
When comes in contact with HCl becomes active - Pepsin
Pepsin breaks down proteins into shorter peptides
Rennin is enzyme in infants which lets milk stay in stomach longer
Fats take longest to digest

Large Intestine

Ascending, Transvers, Descending Colons, Rectum, Anus
1st part of Ascending Colon called Caecum
Appendix comes of Caecum
No villi or enzymes in LI
Glandular cells secrete mucus
Movt in LI 18-24hrs
Water absorption
Bacteria breaks down organic material
CHO, proteins + aa broken down + release CO2, methane, H2S

Effect of Diet on Alimentary Canal

Large meals stretch stomach, Food enters SI faster
increase protein or fat slows mov't in SI
Alcohol/Caffeinestimulate mov't

Cell Membrane

double membrane protecting cell

Homeostasis

environment is kept constant

Intracellular fluid

Space within a cell (cytoplsm)

Interstitial fluid

Fluid outside the body cell
makes up 75% of extracellular fluid

Extracellular fluid

fluid outside the body cells
includes plasm and interstitial fluid

Phospholipid bi-layer

1. hydrophilic head (water loving)
2. hydrophobic tail (water hating)

Cell membrane

selectively permeable/ semi-permeable/ differentially permeable
allows some substances to cross more easily then others

Passive

doesn't require energy

Active

requires energy

Functions of cell membrance

Physical barrier - separates cytoplasm and extracellular fluid
Regulates materials entering + leaving cell
Sensitivity - receptors sensitive to particular molecules
Support - internal part of CM attached to microfilaments of cells cytoskeleton

Membrane Protiens

1. Channel proteins
2. Carrier proteins
3. Receptor proteins
Cell-identity markers

Diffusion -Simple Diffusion

- Gases and liquids
- Movement of molecules form high concentration to low concentration
- Concentration gradient is difference in concentration

Diffusion - Osmosis

- Diffusion of a solvent (water) across a selectively permeable membrane
- Osmotic pressure - level of liquid on water side dropped resulting in high pressure

Facilitated Diffusion/ Transport

Proteins allow molecules to be transported across membrane
Channel proteins + Carrier Proteins
Protein channels is a passive process

Carrier Mediated Transport

Carrier proteins are only open on 1 side at a time
only work with 1 ion or molecule

Vesicular Transport

Active process
1. Endocytosis - entering cell
A. Phagocytosis - cell eating (specialised)
B. Pinocytosis - cell drinking (all cell)
2. Exocytosis - leaving cell

Why are cells small

increase surface area since they have a large SA to volume ration

Enzymes

proteins that catalyse specific chemical reactions without being altered

Features of Enzymes

1. All are proteins
2. All speed up reactions
3. Enzymes not used up in reaction
4. All are reaction-specific
5. Each works under specific conditions (PH, temp)
6. Lower energy of reaction
7. Enzymes work on lock-key
8. Often have co-enzymes + co-factors
9. Denatured by heating

Activation Energy

Energy required to start a chemical reaction
Enzymes lower it therefore lowering body temp

Lock and key model

Enzyme and substrate fit exactly to form the enzyme-substrate complex

Induced fit model

enzyme and substrate join, form weak bonds, cause shape of enzyme to change

Substrate

molecules on which enzymes act on

Active site

part of enzyme that combines with substrate

Denaturing

Shape of enzyme can be changed by heating or poison and will no longer function

Factors affecting Enzyme Activity

Higher the concentration of enzyme = faster rate of chemical reaction
PH - optimal at around 8
Temp - 30-40
Substrate concentration - increases rate of reaction
Products - continually removed

Co-Factors

Non-protein inorganic molecules
change shape of active site

Co-Enzyme

non-protein organic molecule
eg: vitamins + water

Metabolism

all chemical processes that take place in the body

Catabolism

Catabolic reaction where molecules broken down to smaller ones
Eg: Digestion, cellular respiration
Releases energy

Anabolism

Anabolic reactions where small molecules are built up
Requires energy
Eg. Protein synthesis

Protein Synthesis

Long chains of amino acids
20 common types of AA

Cellular respiration takes place

takes place in cytoplasm and mitochondria

Anaerobic formula

Glucose -> Lactic acid + ATP

Aerobic formula

Glucose + Oxygen -> CO2 + H2O + ATP

Cellular respiration

1. Glycolysis - doesn't require oxygen = 2 Pyruvate, 2 ATP
2. Pyruvate broken down by acetyl coenzyme A into CO2
3. Acetyl COA enters kreb cycle or citric acid cycle = carbon atom released each acetyl COA produce 1 ATP
4. electron transport system uses oxygen to pass electrons between molecules producing water + (26-34 ATP)
5. Total ATP ranges up to 38

ATP

60% of energy lost
ATP - adenosine triphosphate
ADP adenosine diphosphate
When phosphate molecule stripped from ATP energy is released

Aerobic Respiration def

process by which energy is released in cells in presence of oxygen

Anaerobic Respiration

Process which energy is released in cells in the absence of oxygen

Oxygen Debt

Heavy breathing occurs after intense exercise to break down lactic acid produced

Nutrients

organic (H, O, N, S)
1. Carbohydrates
2. Lipids
3. Protein
4. Nucleic Acid
Inorganic
1. Water
2. Vitamins
3. Minerals

Carbohydrates

Polysaccharides
eg. starch, glycogen
Disaccharides
eg. Sucrose, maltose, lactose
Monosaccharides
eg. glucose, fructose, galactose

Carb - Mono - disaccharides

Sucrose = glucose + fructose
Maltose = glucose + glucose
Lactose = glucose + galactose

Carbohydrates main use

Energy source for cellular respiration
stored in liver and muscle

Lipids

fats and oil, produced by fatty acids and glycerol
some fatty acids are essential (omega 6)

Lipids - Triglycerides

1 glycerol + 3 fatty acids

Lipid classification

Low density lipids - form plaque + associated with cardiovascular disease 'bad'
High density lipids - good lipids

Lipids uses

1. Energy source
2. Energy storage
3. Insulation
4. Protection of organs
5. Structural functions
6. Metabolic functions
7. Chemical messengers

Proteins contain

Carbon
Hydrogen
Oxygen
Nitrogen

Complete protein

contains full range of AA
eg. milk, animals

Incomplete proteins

contain low levels of 1 or more essential AA
eg. plants

Nucleic acids

H, O, C, N, P
made up of nucleotides

Nucleic acid - RNA

Single chain
carriers info from DNA to where protein made in cell

Nucleic acid - DNA

double helix
genetic material in nucleus

Vitamins

Essential in small quantities
Most act as coenzymes
13 known vitamins most found in food

Vitamin solubility

B, C water soluble
A, D, E, K fat soluble absorbed in gut

Vitamin Deficiency diseases

A - night Blindness
B1 - Beriberi
B3 - pellagra
B6 + B12 - anaemia
B9 - (folic acid), miscarriage
C - scurvy
D - rickets

Dietary Minerals

Chemical elements required by living organisms, other then C, H, N, O
Occurs in all natural food

Water

Fluid which other substances are dissolved in

6 Functions of Digestive system

1. Ingestion of food + water
2. Mechanical digestion
3. Chemical digestion
4. Movement of food along Alimentary canal
5. Absorption of digested food + water into blood and lymph
6. Elimination of material

Types of digestion

Chemical - Enzyme
Mechanical - physical

Mechanical Digestion

physical breakdown of food into smaller pieces increasing SA
Teeth cut, tear + grind food
Churning action in stomach
Gall bladder releases bile

Chemical Digestion

Enzymes break large, complex molecules into smaller, simple molecules
Carbohydrates - split into monosaccharides
Proteins - Peptides, AA
Lipids - Fatty acid, Glycerol
Nucleic acid - Nucleotides

Digestive pathway

Mouth
Oesophagus
(cardiac sphincter)
Stomach
(pyloric sphincter)
Small intestine
Duodenum
(^ Liver, Gallbladder)
(< Pancreas)
Large intestine
Rectum
Anus

Mechanical - Mouth

Mastication - Chewing action of teeth
2.1.2.3
4 incisors
2 canines
4 premolars
6 molars

Chemical - Saliva

Saliva secreted by salivary glands - Salivary Amylase
1. Mucus lubricates food
2. Dissolves food
3. mucus hold food together - Bolus
4. Salivary amylase breaks down starch
5. Antibodies kill bacteria in food

Bolus formation

Tongue pushes bolus down pharynx into oesophagus

Oesophagus

4 layers
1. Mucosa
2. Submucosa ( glands, connective tissue, blood vessel, lymph)
3. Circular + Long muscles
4. Serosa (Connective tissue)
Peristalsis: contractions allowing food to move down

Absorption in Stomach

Alcohol and aspirin is absorbed

Small intestine

Pyloric Sphincter regulates chyme entering SI
Contains projections - Villi, Microvilli
6 meters
Made of
1. Duodenum
2. Jejunum
3. Ileum

SI - Mechanical

Segmentation sloshes content back and forth in digestive juices
Liver produces bile
Gall Bladder stores Bile
Bile enters Duodenum and emulsifies fats

Absorption in SI

SI increase SA due to long length + Villi, Microvilli folding
Inside Villi walls is capillary network + Lacteal (lymph vessel
Blood in capillaries travel to liver to be cleansed
Chylomicrons in lacteal link up with other lymph vessels

Rectum + Anus

peristalsis pushes material in LI into rectum
Walls of rectum stretch
Controlled by Anal sphincters
Eliminated out of anus

Constpiation

If LI mov't decreases content becomes drier and harder
Due to
decrease exercise
emotional problem

Diarrhoea

Due to
Irritation of S or LI
Material moves through too quick
Cancer
Bacterial infection
Coeliac disease
Lactose intolerance

Importance of soluble fibre

Decrease
Chol in blood
Heart disease
Cancer
Help blood, glucose levels
Absorption of fat

Bowel cancer

Uncontrolled growth of cells in wall of LI
Due to diet
increase red and processed meat, low fibre

Coeliac Disease

Unable to tolerate protein - gluten
if eaten immune system destroys Villi in SI
No villi, absorption doesn't happen
Inherited, no cure

Muscle - Skeletal

- Voluntary
- Attached to bones
- Moves them by contradicting and relaxing voluntary nervous system

Muscle - Smooth

- involuntary
- In wall of organs allowing them to expand and relax
- Alimentary canal facilitates the peristaltic wave moves food
- In the eye changes shape to bring focus to object

Muscle - Cardiac

- Involuntary
- Makes heart beat

Nervous Tissue

- Transmits electrochemical impulses from 1 neuron to the next
- Controls + coordinates body activities

Epithelial Tissue

- Protection, Secretion, Absorption

Epithelial - Simple Squamous

- flat usually found lining surfaces that require smooth flow of fluid
found in the;
- Alveoli
- Lungs

Epithelial - Simple Cuboidal

- Typically found in tissues that secrete or absorb substances
found in the;
- Ducts
- Kidney

Epithelial - Columnar

- long thin columns, found in places that secrete mucus
found in the;
- Bronchi
- Uterus