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Introduction to biology
Transcript of Introduction to biology
They are Protein in nature
They act as Biological catalysts
They are Specific in their action
They are affected by changes in Temperature and PH
They are either Intracellular or Extracellular Types of Enzymes:
a) Builders : They are used in building up proteins, fats, carbohydrates and photosynthesis. b) Breakers : They are used in digestion of proteins, carbohydrates, fats and respiration. Factors affecting Enzyme activity:
Substrate concentration A substrate :
A substance which is acted upon by an enzyme to give
a product. Uses of Enzymes: Antibiotics Meat And Leather Production Making Baby Foods Making Sugar Making Juices Baking – Brewing – Cheese Making Biological Washing Powders
•The substrate enters the active site of the enzyme.
•The reaction takes place.
•The substrate exits the enzyme as two simpler products. The figure above shows the function of enzymes: Nutrition
Nutrition is taking in nutrients which are organic substances and mineral ions, containing raw materials and energy for growth and tissue repair, absorbing and assimilating them. Types of nutrition : Autotrophic Heterotrophic Holozoic Saprozoic Parasictic Symbiotic Ingests and digests
its food inside the body. Feeds on dead remains
and digests the food outside
the body: eg. Fungi and Bacteria Feeds on another organism
causing it harm: eg. Worms Exchanges benefit with
another living organism:
eg. Nodular bacteria Herbivore: feeds on
plants only. Carnivore: feeds on
only (meat). Omnivore:
feeds on both
plant and animal. Can make its own food Feeding on ready made food Nutrients The 7 nutrients :
•Water Mr. Muscles & Animal Nutrition Animals eat to grow, repair etc. They simply eat to live. In this unit we will study how animals make use of what they eat. The journey of the food from the mouth to the anus through the alimentary canal includes 5 steps: 1.Ingestion: Taking in pieces of food into the mouth
2.Digestion: The break down of large, insoluble food molecules into smaller more soluble ones by chemical and mechanical means.
3.Absorption: Taking the digested food molecules into the cells
4.Assimilation: Making use of the digested food molecules for example to release energy or grow etc.
5.Egestion: The elimination of undigested food materials through the anus The Liver : Functions of the liver:
Formation of 4:
1-Glycogen out of excess glucose
2-Urea out of deamination of excess
3-Bile out of destroyed red blood cells
4-Plasma proteins Storage of 4:
1-Deamination of excess amino acids
2-Destruction of old red blood cells
3-Destruction of alcohol
4-Detoxification of toxic metabolites e.g: drugs and hormones Alimentary canal
Teeth are small, calcified, whitish structures found in the jaws (or mouths) of many vertebrates that are used to break down food. Teeth Incisors:
They are 4 in front of each jaw.
They act like a blade to cut food(eg. To cut a bite of a sandwich) they have a (chisel-like surface).
They are two in each jaw.
They are very pointed, in humans they are used for the same purpose as incisors.
However in carnivores they are longer and sharper and used to kill the prey.
4 on the sides of each jaw
They are used to cut and grind food.
They are 6 at the back of
Each jaw, 2 of them are wisdom teeth. They have the same use as Premolars. Plant Nutrition Photosynthesis :
It's the process by which green plants manufacture simple sugar from simple inorganic raw materials, using light energy and photosynthetic enzymes. Equation of photosynthesis: Structure of Dicotyledonous leaf : Factors Needed For Photosynthesis:
• Carbon Dioxide
• Light Factors Affecting The Rate Of Photosynthesis:
• Amount of water: the rate increases as it increases
• Concentration of carbon dioxide: the rate increases as it increases
• Light intensity: the rate increases as it increases Green House: Transport In Humans Humans have two transport systems: A) Circulatory system: which consists of 1) A pump 'The Heart' 3) Blood 2) Blood Vessels B) Lymphatic system: which consists of 1) Lymph nodes
3)Lymph The Heart It's a muscular organ which acts a a pump
It receives and sends blood to all body parts
It's found in the chest cavity
It's made of Cardiac muscle fibers
It receives blood supply through the coronary arteries Mechanism of the Heart : Transport In Plants Structure Of Plants: Shoot : Above the soil Root : Below the soil Plant tissues : xylem tissue Phloem tissue Transpiration
Translocation The Respiratory System Human respiratory system : Nose
Alveoli (air sacs) Gas Exchange (Breathing): Effects of Smoking Excretion in Humans Excretion is the removal of waste products, harmful materials and toxic substances produced during metabolism The Urinary System: Homeostasis It's the maintenance of a constant internal environment within a living organism,so that every organ and cell is provided the perfect conditions to perform its functions. Temperature Regulation: The role of the skin in regulating body temperature : A healthy human should have a body temperature of 37°C A) Cooling Down the Body:
Hairs lie flat B) Heating Up the body:
Hairs become erect Blood Glucose level regulation: Role of Insulin ( Hyperglycemia)
Role of Glucagon ( Hypoglycemia) Normal Blood Glucose Level: 80-100 mg per 100cm3. The Pancreas Co-ordination and Response Sensitivity : The ability of living organisms to detect stimuli
Irritability: The ability of living organisms to detect and respond to stimuli
Coordination: The way all the body organs and systems work together Two organ systems are continuously working to detect and respond to stimuli, these organ system are called the Nervous system and the Endocrine system The Nervous System:
The nervous system is a system of organs working together to detect and respond to stimuli. The nervous system is made up of two systems, the Central Nervous System (C.N.S) and the Peripheral Nervous System (P.N.S) the peripheral nervous system connects the central nervous system to the other parts of the body. Reflex action:
A reflex action is a rapid,sudden,automatic
involuntary response to a stimulus by a muscle
or a gland which does not require control. Examples of reflex action:
Coughing reflex Reflex Arc: It's the pathway taken by nerve impulses which work during a reflex action.
RECEPTOR → Sensory Neurone → CNS → Motor Neurone → EFFECTOR The Endocrine System:
The endocrine system is system of ductless glands,
which release their secretions directly into the blood stream to reach specific target organs. Hormones are chemical substances produced by a gland (Protein or lipid), carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liver. Examples of endocrine glands: THE EYE Facts about the eye :
The human eye can distinguish about 10 million colors.
that the retina contains 120 million rods for "night vision", and 8 million cones that are colour sensitive and work best under daylight conditions.
About 80 % of what we perceive comes through the eyes. Our memories are made 80 % by images. The eye comes with information about the depth, distance, shape, color and movement of the objects. Structure of the eye Reproduction It's the ability of living organisms to produce new offspring similar to themselves to keep their kind (Species) Types of reproduction: Asexual reproduction Sexual reproduction Reproduction in flowering plants Stages of Reproduction in flowering plants : Dispersal of fruits and seeds Seed and Fruit formation Fertilization Pollination Structure of a Flower Female reproductive system
Human Reproduction Male reproductive system The menstrual cycle It's the cyclic changes that occur in the ovary and the uterus every 28 days. STD's: