Cell Specialization:
- All cells begin alike and differentiate into specialized cells
- They have a different structure and ability to preform their specific functions
- Group of cells work together to preform functions
- There are 200 different types of cells in the human body
Stem Cells
Sources of stem cells
- Embryonic stem cells
- Umbilical cord
- Adult stem cells
All stem cells have the potential to become specialized cells
All cells start their lives as identical cells called stem cells
The Cell Cycle
Why do cells divide?
-Growth
-Repair
-Replace
-Reproduction
Cells divide during interphase
During interphase, the cell:
- Grows
- The nucleus is visible
- Replication of DNA
Mitosis
Prophase:
- Chromatin coils into chromosomes
- Nuclear membrane disappears
- Centrioles migrate to poles
- Spindle fibres from like-webs expand from centrioles and pull
Metaphase:
- Chromosomes line up in the middle
Anaphase:
- Chromosomes move away from each other
Telophase:
- New nuclear membrane
- Spindle fibres disappear
- Chromosomes unwind and turn into chromatin
Causes of mutations in the cell:
- Carcinogens
- Radiation
- Viruses
Cytokinesis - When the cytoplasm is divided in half
In an animal cell, a cleavage furrows
In a plant cell, the pre-mature cell wall forms
Malignant Tumors vs Benign Tumors
Malignant tumours are harmful and could spread
Benign tumours are not harmful, but need to be monitored just in case
Normal Cells vs Cancer Cells
Cancer Cells
- Do not stop reproducing
- Make exact copies of themselves through mitosis
- Do not stick to other cells
- Behave independantly
- Can move to another location in the body
Normal Cells
- Make exact copies of themselves through mitosis
- Reproduce for about 50-60 cell divisions
- Self-destruct when too old or damaged
- Stick together to form masses of cells as appropriate
Coronavirus
Belongs to a family of viruses called Coronaviriae
Originates from an animal
Enters the cell through the ACE-2 receptor
COVID-19
First discovered in Wuhan, China in December 2019
Came from bats, with pangolins being a likely carrier
Some who get COVID-19 will get Acute Respiratory Distress Syndrome.
The alveoli gets filled with fluid, which makes it difficult for gas exchange to occur. Therefore, cells do not get enough oxygen.
Diarrhea and vomiting are symptoms
What makes COVID-19 different than the flu
- COVID-19 seems to spread easier than the flu
- COVID-19 is more serious
- Symptoms of COVID-19 take longer to appear
- COVID-19 is more contagious
- Everyone experiences COVID-19 differently
Plant Organs:
- Epidermal
- Ground
- Vascular
- Meristematic
The Digestive System
The digestive system breaks down food and nutrients and supplies cells with nutrients for growth, maintenance and repair.
Stages of the digestive system:
1. Indigestion
2. Digestion
3. Absorption
4. Egestion
The Immune and Lymphatic System
Cells involved
Leukocytes - white blood cells that protect the immune and lymphatic system. They detect antigens.
Phagocytes - consume foreign bodies
Lymphocytes - destroy the bad cells
Cytokines - Immune system proteins
The Respiratory System
Respiratory Tract - lined with epithelial cells, which are covered in hair-like cilia. This helps moisten and filter the air to prevent dirt, dust and particles from reaching the lungs.
Trachea - Supported by rings of cartilage, which keep the trachea open for easy transport of air
Bronchi - designed to carry air into the lungs. They're supported by cartilage, but branch further into many tinier tubes
Alveoli - Microscopic air sacs that are at the end of the bronchi tubes. Oxygen and carbon dioxide are exchanged with the blood, since each alveolus is surrounded by its own capillary.
Cell organelles and their functions
Mitochondria
- Makes the energy for the cell
- Self-replicating
- Distributes the energy it creates evenly throughout the cell
Endoplasmic Reticulum
- Transports proteins around the cell
- Stores proteins
- Modifies molecules, if need be
Golgi Apparatus
- Produces the membranes and proteins
- Packages proteins and carbohydrates and prepares them to be exported
- Modifies molecules produced by the cell, if necessary
Nucleus
- Controls what goes on in the cell
- Contains, stores and protects DNA
- Directs activities in the cell
Vacuole
- Collects the waste from the other organelles
- Collects large amounts of water
- Digests the food materials in the cell
Ribosomes
- Produces proteins
- Clings onto the endoplasmic reticulum
- Scattered throughout the cytoplasm
Nuclear Membrane
- The membrane surrounding the nucleus
- Allows proteins to pass in and out of the nucleus
- Defines and decides the boundaries that surround the nucleus
Cytoplasm
- Where the organs are located
- Made up of salts, minerals and nutrients
- Can change the cells shape
Cell Membrane
- Protects the cell
- Decides what comes in and out of the cell
- Lets the good in, and gets rid of the bad
Parts of an atom
Protons - positively charged with a mass of 1
Electrons - negatively charged with a mass of 0
Neutrons - neutrally charged with a mass of 1
Ions - any element with a negative or positive charge.
Cations are positive ions, anions are negative ions.
The law of conservation of mass states that mass is neither
created nor destroyed during chemical reactions.
Types of Chemical Reactions
Synthesis - two elements combined into one
Decomposition - to break a compound into two elements
Single Displacement - to replace another element in a compound
Double Displacement - when the cations in two ionic compounds switch places
Combustion - when a substance reacts with oxygen gas, releasing energy in the form of light and heat
Neutralization - when an acid and a base react to form a salt and involves a combination of hydrogen and OH- ions to generate water.
Acids and Bases
- Corrosive
- Dissolves in water
- Conduct electricity
Acids - sour, contains non-metals, makes hydrogen
Bases - bitter, contains metals, makes hydroxide, feels slippery
pH Scale - The measure of how acidic or basic water is
Chemical Reactions
Hints a Chemical Reaction Has Occurred
- Smell
- Colour
- Precipitate
- Hard to reverse
- Sound
- Gas
Ways to Represent a Chemical Reaction
- Word equation
- Skeleton equation
- Balanced equation
Covalent bonds: Bonds that are created because electrons are being shared
Example: Hydrogen and oxygen share each others electrons in order for them to become stable.
Light - a wave of energy that travels in straight lines which illuminates things.
Light travels at 300,000 km per second.
Light travels through different types of mediums
Transparent Mediums - all light passes through
Translucent Mediums - some light passes through, not all
Opaque Mediums - no light passes through
Waves on the electromagnetic spectrum:
- Radio waves
- Microwaves
- infrared waves
- Visible waves
- Ultraviolet waves
- X-rays
- Gamma rays
Non-luminous: Objects we see because light passes through them or reflects off them.
Luminous: Objects that produce light
Light travels straight through until it hits something - depending on the material, light will behave differently.
Colour Theory
Additive Primary Colours:
Red, green and blue.
Secondary Colours:
Cyan, magenta, yellow
Different percentages of cyan, magenta and yellow are used to generate different colours.
Objects absorb all colours except the colours being seen, which is reflected.
Difference Between Climate and Weather
Weather is:
- Short-term
- Immediate - happening at the moment
- Weather conditions at a particular time and place
Climate is:
- Long-term
- The average after a long period of time
- Average wind speed
- Average wind direction
The darker the surface, the more the sun will reflect it back.
Earth's Spheres:
Each of these components receive the sun's energy, traps it, stores it and transports it until it all radiates back out to space.
Atmosphere - gas surrounding Earth
Hydrosphere - liquid water, water vapour and ice
Lithosphere - solid rock, minerals (Earth's crust)
Biosphere - all plants, animals, bacteria, etc.
Combustion - fast reaction of a substance with oxygen to produce oxides.
Fuel + Oxygen -> Oxides + Water + Energy
Incomplete Combustion - occurs when burning happens, but there is not enough oxygen.
Greenhouse gases are a natural way for the Earth to stay warm
Four Contributors to Greenhouse Gases:
- Water vapour
- Carbon Dioxide
- Methane
- Nitrous Oxide
Earth naturally keeps these in balance so the atmosphere keeps the temperature ideal for the biosphere.