mid-year review sec 3 2012-2013. science review: part 1 the living world
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Mid-Year review
Sec 3
2012-2013
Science Review: Part 1
The Living World
Cells
• The smallest “unit” of life is the cell
Name of Part Function
Nucleus Contains the DNA
Controls the cell’s activities
Cytoplasm Liquid in the cell
Cellular membrane Controls what enters and exits the cell
Cells
• Cells have many different functions– They can be nerve cells, sex cells, blood
cells, ect…
– Cells → Tissues → Organs → Systems
Cells
• How a cell divides (multiplies itself to ensure growth and repair) depends on the function of the cell
– All cells (except sex cells) muliply via mitosis
– Gametes (sex cells) are produced via meiosis
Characteristics of Mitosis:
• 1 parent cell (23 pairs of chromosomes)
• Duplicates its DNA
• Splits into 2 identical cells (23 pairs of chromosomes)
Characteristics of Meiosis:
• 1 parent cell (23 pairs of chromosomes)
• Duplicates its DNA• Splits into 2 identical cells
(23 pairs of chromosomes)
• Each daughter cell splits again forming a total of four genetically unique cells with only 23 chromosomes
To summarize…
MitosisMitosis MeiosisMeiosisOccurs for all cells except gametes (sex cells)
Occurs only in gametes
Produces 2 cells Produces 4 cells
Produced cells are identical Produced cells are genetically different
End cells have 23 pairs of chromosomes
End cells have 23 chromosomes
• Genetically Modified Organism (GMO)– Occurs when we tinker with the DNA of a cell.– By changing the chromosomes in the nucleus
we can give different characteristics to the organism
• Resist frost• Spider goat
Cells
• In order to perform their function, cells require energy, which they get by performing cellular respirationcellular respiration
Glucose + Oxygen → Carbon dioxide + water + ENERGY
Digestive System
• Role of the digestive system:– Decomposes food into smaller nutrients– Absorbs nutrients and water– Eliminates waste
Topic 1: The Digestive System
• Nutrients– Function– Energy value– Broken down elements
• Anatomy
• Physiology
Nutrient Chart
NutrientsNutrients FunctionFunction Energy Energy valuevalue
SourceSource Broken Broken down intodown into
Carbs 1st energy supply
17 kJ/g Breads, sugar, pasta
Glucose
Lipids (fats) 2nd energy supply
37 kJ/g Oils, butter, meats
Glycerol
Fatty acids
Proteins Emergency energy supply
Helps build and repair tissues
17kJ/g Meats, nuts Amino Acids
Nutrient Chart
NutrientsNutrients FunctionFunction Energy Energy valuevalue
SourceSource Broken Broken down intodown into
Water Regulates Metabolism
None Fruits, vegetables, water
Absorbed directly
Vitamins Regulates Metabolism
None Fruits, vegetables
Absorbed directly
Minerals Regulates Metabolism
None Fruits, vegetables
Absorbed directly
Fiber Regulates Metabolism
None Fruits, vegetables
Not absorbed
• What are the energy giving nutrients?
• If you are injured what nutrient should you eat?
• What is a source of carbohydrates?
• Calculate the energy value of a cookie with 6 g of carbs and 12 g of fats?
• What do proteins break down into?
• Name the nutrients that help regulate metabolism.
C is for Cookie?
Or Calculation?
C is for Cookie…
Cookies:
Protein 2.1 g
Fat 7.7 g
Carbs 24 g
2.1 g x 17 = 35.7 kJ
7.7g x 37 = 284.9 kJ
24 g x 17 = 408 kJ
Total: = 728.6 kJ
Function:Function:These cookies are therefore an These cookies are therefore an energy energy producerproducer but are also very high in fat but are also very high in fat
C could be for last minute CRAM
Topic 1: The Digestive System
• Nutrients
• Anatomy– The digestive tract– Sites of Absorption
• Physiology
Physiology
Mmmm!!
Burger
Anatomy
• The digestive system:– The digestive tract
• Path the food takes
– The digestive glands• Where chemicals that help in the breakdown of
food comes from
Glands = organs that secrete an enzyme (chemical)
Anatomy
• The digestive tract
–The Mouth– The Pharynx– The Esophagus– The Stomach– Small Intestine– Large Intestine
Anatomy
• The digestive tract– The Mouth
–The Pharynx– The Esophagus– The Stomach– Small Intestine– Large Intestine
Shared by the respiratory system and the digestive system
Anatomy
• The digestive tract– The Mouth– The Pharynx
–The Esophagus– The Stomach– Small Intestine– Large Intestine
PERISTALSIS: muscle contractions that push food through the digestive tract
Anatomy
• The digestive tract– The Mouth– The Pharynx– The Esophagus
–The Stomach– Small Intestine– Large Intestine
*Churning: action of the stomach to mix the food with the gastric juices
Anatomy
• The digestive tract– The Mouth– The Pharynx– The Esophagus– The Stomach
–Small Intestine– Large Intestine
*Peristalsis
*Site where nutrients are absorbed
Anatomy
• The digestive tract– The Mouth– The Pharynx– The Esophagus– The Stomach– Small Intestine
–Large Intestine
Topic 1: The Digestive System
• Nutrients
• Anatomy
• Physiology– How does the system work
Physiology
Mmmm!!
Burger
What happens?
• Mouth:– Mechanical breakdown: chewing– Chemical breakdown of carbscarbs because of the
saliva from the salivary glands
What happens?
• Pharynx:– Not Much
What happens?
• Esophagus:– Mechanical breakdown: Peristalsis
What happens?
• Stomach:– Mechanical breakdown: churning– Chemical breakdown of proteinsproteins because of
the pepsin from the gastric glands– Chemical breakdown with the stomach acid
What happens?
• Small Intestine:– Mechanical breakdown: peristalsis– Mechanical breakdown of lipids because of
the bile from the liver
– Chemical breakdown of all foodall food because of the Intestinal juices
• Major part of digestion occurs
What happens?
• Large Intestine:– Mechanical breakdown: peristalsis
• Where do carbs get chemically broken down?
• Where do proteins get chemically broken down?
• Where do the lipids get chemically broken down?
• Into which part of the digestive tract does the liver and pancreas secrete their enzymes?
Physiology
• During the digestion process your food undergoes mechanical and chemical transformations
– Mechanical Transformation: same thing only smaller or mixed
– Chemical Transformation:break down of complex molecules into less complex molecules
Examples of Mechanical Transformations
• The Mouth – Chewing
• The Stomach and small intestine- Churning– Mixing food with the secretions of the
digestive glandsPeristalsis is also a mechanical transformation
Physiology
Mmmm!!
Burger
Absorption of nutrients
• The process that moves nutrients (chemically broken down food) through the lining of the digestive tract and into the blood stream.
• Mostly, food is absorbed in the small intestine via Villi.
What is a Villi?
• Folds in the intestine
• Increases surface area
• The small intestine absorbs:– Lipids (fatty acids and glycerol)– Carbohydrates (glucose)– Proteins (amino acids)
• The large intestine absorbs:– Water– Vitamins– Minerals
Physiology
Mmmm!!
Burger
The Material World
In less than 30 minutes
• Everything around us is made of atoms and molecules
• To simplify how we see things, we will represent these tiny atoms and molecules using the particle model
• An element is more of the same particle
• A compound is when there are two or more types of elements/ atoms in a molecule (the particles must be touching)
Elements turn into compound through chemical reactions that result in a gain of mass or a change of color
Moral of the story
• A pure substance is when a substance has the exact same chemical composition
• A mixture is well, a mixture
Moral of the story
• A pure substance is when a substance has the exact same chemical composition
• A mixture is well a combination of more than 1 type of molecule or element
• Would salt water be considered a pure substance?
• What are the 2 signs for changing an element into a compound?
• Is O2 an element or a compound?
Physical Change vs. Chemical Change
• Physical Change– The chemical nature of the substance stays
the same• Dillution• Dissolution• Phase Change
• Chemical Change– The chemical nature of the substance is
altered
Properties
Density
• Density (ρ) is mass on Volume– ρ = m/V
• ρ is different from p
• m = How much matter it has• V = how much space does it take up
The General rules…
Regular solids
Irregular solids
Liquids Unit
mass Weigh Weigh Liquid mass g
Volume Length x width x height
Water Displacement
Measure it in the graduated cylinder
ml or cm3
Density m Weigh Liquid mass g/ml or g/cm3
v Water Displ. Measure in g.c.
Identifying solids
• Best to verify density
• Color
• Electrical conductivity
• Boiling point
• Melting point
• Magnetism
Identifying liquids
• Cobalt Chloride – positive test = water
• Electrical conductivity– positive test = either salt water, acid or base
• Blue litmus paper– if it turns red = acid
• Red litmus paper– if it turns blue = base
Identifying Gases
• Flaming Splint– Positive test = hydrogen
• Glowing splint– Positive test = Oxygen
• Limewater– Positive test = Carbon Dioxide
Graphical Language
1. There exists many ways to represent an object
a) Sketch vs. diagram vs. Technical Drawing
The difference
• A Sketch– Drawing made without instruments or
measurements
• A Technical Drawing– Drawing made with instruments, made to
scale, and serves as a reference, therefore it follows conventions
• Technical drawings include– Diagram of principles
• Shows how the object works
– Construction diagram• How to build the object
Sketch it
2. In order to properly communicate through technical drawings, we need a common set of conventions (rules)
to follow.
a) Lines
Line type Function
Visible Line Shows the visible details of an object
Hidden Line Shows the hidden details of an object
Center Line Shows the center of a circle
Dimension Line
Indicates a dimension (mm)
Extension Line
Indicates from where a measurement is taken place
a) Lines (cont.)
Line type Function
Cutting Plane Line
Indicates the position of an imaginary cut
Hatched Line
Shows the surface that has been cut
Leader Line Points to a specific part of the drawing
b) Scale
• The scale:– A relationship between an object’s dimensions
in a drawing and the object’s actual dimension
– Drawing size : Real Life size• 1:1 = actual size representation• 2:1 ; 3:1; 25:1 = scale of enlargement• 1:2 ; 1:4; 1:25 = scale of reduction
c) Perspective
• Definition:– A form of representation that gives the
impression of depth
– Yet can distort the image when drawing it in 2D
D) Projections
• i) Multiview– Shows a detailed view (using various lines) of
3 sides of an object without distortion
Top
Front Side
D) Projections
• ii) Isometric– 3D representation of an object that shows all
three sides at once
c) Projections
• iii) Oblique– Representation of an object using
perspective. – The drawing is highly distorted (depth
reduced by half)
C) Projections
• Axonometric– Exploded view of an object showing how to
assemble it
– Will always be accompanied with a list of materials (nomenclature)
Mechanical Engineering
Assembling parts
1. There are certain components in technical objects that serve
specific purposes to ensure the proper functioning of the system
a) Typical functions to ensure proper functioning
• Sealing– To seal
• Lubricating– To reduce friction
• Guiding– Allows specific motions
• Links– To connect components together
2. Guides allow a component to move in a specific manner
2. Guides
• Freedom of motion– Rotation and/or translation around the x, y, or z
axis
• Types of guides– Rotational guide: ensures rotation– Translation guide: ensures translation– Helical guide: ensures rotation
and translation around
the same axis
3. Links connects different parts of a technical object together
a) Each link will have 4 characteristics
Direct Indirect
Flexible Rigid
Removable Non-Removable
Complete Partial
b) Characteristic definitions
• Direct: – The two pieces fit
without requiring another component
– E.g. puzzle pieces– E.g. Pen cap and the
pen
• Indirect:– The two pieces need
an extra component to hold them together
– E.g. A poster and the wall
– E.g. 2 pieces of paper
b) Characteristic definitions
• Flexible: – The linking component
or materials are flexible
– E.g. Sticky tack– E.g. velcro
• Rigid:– The linking component
or materials are non flexible
– E.g. A nail– E.g. a dowel and a
base
b) Characteristic definitions
• Removable: – Can be removed
without damaging the material or linking component
– E.g. Screw– E.g. Sticky Tack
• Non-Removable:– Cannot be removed
without damaging the material or linking component
– E.g. A nail– E.g. Glue
b) Characteristic definitions
• Complete: – Does not allow any
movement between the pieces
• Partial:– Allows some
movement between the pieces
Technological Drawings
1. Sketch vs. Diagram vs. Drawing
Sketch vs. diagram vs. drawing
• Sketch : quick free hand drawing
• Diagram: (how the object is made)
• Drawing: (how the object looks)
2. Basic lines
Basic Lines
• Visible Contour Line
• Hidden Contour Line
• Center Line
• Extension Line
• Dimension Line
What is the difference?
What is the difference?
3. Types of Projections
Projections
• Oblique– 1 face is parallel to the paper– Depth is altered
Projections
• Orthogonal– Isometric
• All three sides are shown
Projections
• Orthogonal– Multiview
• Shows all three sides with details
Projections
• Axonometric– Shows in details all parts of an object– Also called the exploded view– Comes with a list of parts (nomenclature)
4. Scales
What is it?
What is it?
Purpose of scales
• Reduction Scale– 1:2– 1 mm in the drawing represents 2 mm in real life
• Enlargement Scale– 2:1– 2 mm in the drawing represents 1 mm in real life
• Actual size representation– 1:1– Object is life size
Scale
• What scale would you use to draw a …– Train– Spider– A parc statue– A pencil
5. Cross-Sections and Sections
Cross-sections vs Section
• Cross-Sections:– Shows the interior details of an object as if it
were cut by a cutting plane
• Sections:– Shows the interior details of a part of an
object as if it were but by a cutting plane
Cross-Section
Sections
• Revolved Section • Removed Section
6. Links and Guides
Guides
• Rotational
• Helical
• Translational
Links
Direct Indirect
Removable Non-removable
Partial Complete
Flexible Rigid
7. Properties
Properties
• Malleable
• Ductile
• Hardness
• Elasticity
• Resilience
• Stiffness
Materials
• Ceramic
• Wood
• Modified wood
• Metal
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