dear future scientists, use this study helper to revise
TRANSCRIPT
Science ASP Grade 7 – Elite stream
Sections: 1,2 and 3Teacher: Esra’ M. Jaradat
Dear future scientists,
Use this study helper to revise and study for the exam
If you wanted help go back to the PPTs of lessons 1 – 3 and you can contact me at anytime on teams
Thank you
Teacher Esra' M.Jaradat
Unit 2: Life structure and functionModule 2: Body Systems
Lesson 3Obtaining Energy and Removing wastes
Study Helper
Textbook pages 38 - 49
Teacher Esra' M.Jaradat
Importance of food:1. Source of energy to carry out their cell functions.2. Provides building blocks for growth and repair of tissues.
Calorie The amount of energy it takes to raise the temperature of 1 kg of water by 1◦C
Nutrients The parts of food used by the body to grow and survive like calcium and proteins
The amount of energy a person needs depends on:
Weight , Age, Activity level and Gender Teacher Esra' M.Jaradat
The digestive system
Tongue
Salivary glands
Esophagus
Stomach
Small intestine
Large intestine
Teacher Esra' M.Jaradat
Functions of digestive system
Ingestion Digestion Absorption Elimination
PeristalsisFood moves through the esophagus and the rest of the digestive tract (stomach, small and large intestines) by waves of smooth muscle
contractions.Teacher Esra' M.Jaradat
Path of food
All these are holloworgans (empty from inside) so food can pass through
Teacher Esra' M.Jaradat
Types of digestion
Mechanical digestion Chemical digestion
Food is physically broken into small pieces through grinding, mashing and chewing.
Food is chemically broken into small molecules
Done by teeth and tongue and by peristalsis
Done by enzymes
• Make it easier for swallowing • Increase the surface area of food
molecules to prepare food for chemical digestion
Note: Chemical digestion starts in the mouth, continues in the stomach and is completed in
small intestine
Teacher Esra' M.Jaradat
Mechanical digestion
Chemicaldigestion
Teeth and tongue
• Chewing• Grinding • Mashing
Saliva
• Enzyme that digests carbohydrates• Substance that neutralizes acidic food
Mouth
Saliva is secreted by salivary glands
Teacher Esra' M.Jaradat
Muscular tube that connects the mouth to the stomach.
Esophagus
Mouth
Esophagus
Stomach Teacher Esra' M.Jaradat
Stomach
Stomach connects esophagus to small intestine
Esophagus
Stomach
Small intestine
Teacher Esra' M.Jaradat
Functions of stomach
1. Temporarily store food
Stomach has folds that allow the stomach to expand and store food for few hours.This allows you to go many hours between meals.
2. Chemical digestion
• The cells of the stomach secretes gastric juice.
Gastric juice contains:Gastric acid: to break down the structures that hold the plant and animal cells together
Stomach
Teacher Esra' M.Jaradat
• Where most chemical digestion occurs (digestion of all types of
food: fats, proteins, carbohydrates and nucleic acids)
• Where nutrients and water absorption occurs by villi
• Villi are finger-like projections cover the folds of the small
intestine, each villus has blood vessels
• In villi, nutrients leave the small intestine and go to blood through capillaries
Small intestine
Teacher Esra' M.Jaradat
Folds in small intestine
covered with villi One villus
Blood vessels
Lymph vessel
Teacher Esra' M.Jaradat
Materials that pass in the large intestine are the waste products of digestion (food that is not digested or not absorbed)
Functions of large intestine:
• Absorb any remaining water
• Release of wastes (semisolid) to the outside of body
Large intestine
Teacher Esra' M.Jaradat
Functions of the Excretory System
1. Collect and eliminate wastes
2. Regulation of fluids
Teacher Esra' M.Jaradat
The excretory system is made of 4 systems
System Type of wastes eliminated
Respiratory Waste gases: carbon dioxide and water vapor
Urinary Liquid wastes
Digestive Solid wastes (undigested food)
Skin Excess water and salts through sweating
Teacher Esra' M.Jaradat
How do plants obtain energy and remove waste?
• Plants make their own food through a process called photosynthesis
• Photosynthesis is a series of chemical reactions that use light energy and covert it to usable energy for the cell
• Plants need carbon dioxide, water and light energy to make oxygen and glucose (sugar molecules as food)
Teacher Esra' M.Jaradat
• Roots absorb water and minerals from soil, then they move through xylem to reach all parts of plants
• Leaves make food and it moves through phloem to reach all parts of plant
• Gases in plants pass through stomata (tiny holes in the surface of plant’s leaf)
How do plants obtain energy and remove waste?
Teacher Esra' M.Jaradat