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grade 8 science > Biology > Flashcards

Biology Flashcards

1
Q

What are the three types of microscopes?

A

Simple Microscope: Single lens. 10x-20x magnification

Compound Light Microscope: Two or more lenses. Up to 2000x magnification (most are under 400x). The most common microscope in science classes and medical laboratories.

Electron Microscope: Powerful microscopes used for scientific research. Magnification up to 10 million times.

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2
Q

How do you calculate the magnification of a microscope?

A

Multiply the objective lens (the one near the sample) by the eyepiece lens (the one close to your eye) to get the total magnification.

ie. 4x eyepiece and 10x objective would equal 40x total magnification

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3
Q

What are the seven characteristics of all living things?

A
  1. Made up of cells
  2. Take in nutrients
  3. Need energy
  4. Produce waste
  5. Respond to stimuli
  6. Grow
  7. Reproduce (have babies)
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4
Q

What are the three principles of cell theory?

A
  1. All living things are made up of one or more cells.
  2. All living cells come fro other cells.
  3. The cell is the basic unit of life.
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5
Q

What do you need to see a virus?

A

An electron microscope, because viruses are extremely small.

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6
Q

What are viruses made of?

A

Viruses consist of a piece of DNA covered by a protective protein.

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7
Q

How do viruses reproduce?

A

Viruses reproduce by injecting their DNA into a host cell and tricking it into manufacturing new viruses. The viruses reproduce in the cell, preventing the cell from functioning properly.

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8
Q

What are some examples of viruses?

A

HIV (Human Immunodeficiency Virus), causes AIDS
Influenza
COVID

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9
Q

What is the difference between unicellular and multicellular organisms?

A

Unicellular: describes a single celled living thing
Multicellular: describes a living thing made up of multiple cells (like humans)

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10
Q

What are some of the functions performed by organelles inside a cell?

A

Organelles literally means “little organs” and, like human organs, they perform specific tasks to help keep cells alive. They include:

  1. Providing a structure and form
  2. Forming a barrier between the cell and the environment.
  3. Building and repairing cells.
  4. Synthesizing materials
  5. Storing and releasing energy
  6. Getting rid of waste material
  7. Multiplying in number
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11
Q

What are the three major parts of a cell?

A
  1. Cell membrane: The thin, flexible structure that surrounds the cell. Regulates what enters and exits the cell. Controls the movement of food, waste and other substances.
  2. Nucleus: The ‘brain’ of the cell. Controls the functions of the cell. Contains genetic information through DNA.
  3. Cytoplasm: A jelly-like fluid in which organelles are found. This is where many chemical reactions take place within the cell.
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12
Q

What does the mitochondrian do?

[ an organelle ]

A

Converts the energy stored in food into usable energy for the cell. The ‘powerhouse’ of the cell.

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13
Q

What does the ribosome do?

[ organelle ]

A

Manufactures proteins, the building blocks for structures in the cell.

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14
Q

What does the endoplasmic reticulum do?

[ organelle ]

A

A network of flattened tubes that transport proteins within the cell.

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15
Q

What does the Golgi Body do?

[ organelle ]

A

Sorts and packages proteins in membrane-wrapped structures called vesicles.

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16
Q

What do the Vesicles do?

[ organelle ]

A

Small packages containing nutrients, protein and water.

17
Q

What do Vacuoles do?

[ organelle ]

A

Temporary storage areas. Usually bigger in plants.

18
Q

What do Lysosomes do?

[ organelle ]

A

Contain digestive chemicals that break down food particles, cell wastes and worn-out cell parts.

19
Q

What do Chloroplasts do?

[ organelle ]

A

Only found in plants. Allows photosynthesis to occur: energy from the sun is turned into energy.

20
Q

What is photosynthesis?

A

The process by which plants manufacture their own food. Occurs in chloroplasts. Chloroplasts contain chlorophyll which absorbs light and converts it into chemical energy.

Carbon dioxide + light energy + waster = sugar/glucose and oxygen

21
Q

What is cellular respiration?

A

Animals and plants convert stored energy (sugar) into useable energy for the cell. Takes place in the mitochrondrian. The energy released can then be used by the cell.

Glucose + Oxygen = carbon dioxide + water + energy

22
Q

What are microbes?

A

Very tiny organisms that can only be seen with a microscope. Microbes are everywhere.

23
Q

What are some places where you can find microbes?

A
  1. In your mouth (about 700 species of bacteria live in your mouth).
  2. In the soil. Microbes help break down or decompose dead materials such as rotting wood and leaves.
  3. In fresh water. Microbes known as protists can be found in fresh water such ad ponds.
24
Q

Microbes can be both helpful and harmful. What do we call microbes that make people sick?

A

Pathogens.

25
Q

What are the four main ways that infectious diseases are transmitted?

A
  1. Direct Contact: Shaking hands, sharing bodily fluids.
  2. Indirect Contact: Sneezing, coughing.
  3. Water and Food: Eating food or water infected with pathogens
  4. Animal Bites: Being bitten by an animal carrying rabies.
26
Q

What are some examples of your body’s “first line of defence” against pathogens?

A

Skin: A physical barrier
Sweat and Oils on your skin: Slightly acidic, prevents some pathogens from browing
Gastric Juice: Secreted by the lining of your stomach, kills some bugs
Mucus and Cilia: In your nose and other openings, prevents pathogens from entering the body

27
Q

What is your body’s “second line of defence” against infection?

A

The Innate Immune Response.

A general response. Not specific to a particular type of pathogen. Increased blood flow brings more white blood cells to the infected area.

This can cause swelling, inflammation, fever and redness.

28
Q

What is your body’s “third line of defence” against infection?

A

Acquired Immune Response

A specific attack on a particular pathogen. Your body’s white blood cells and antibodies can memorize specific pathogens by its antigens (unique substances on the surface of the pathogen and invading cells).

If your body has seen a pathogen or virus before, it will easily fight it off. This gives you immunity.

29
Q

What is an Endemic virus?

A

When a virus infects people on a regular but steady rate within a geographic area. Like flu season every year.

30
Q

What is an Epidemic?

A

When a disease occurs above the normal amount for a population in a geographic area.

31
Q

What is a Pandemic?

A

An epidemic that has spread over several countries of continents or throughout the whole world. Example: COVID.

32
Q

Why did Indigenous people get infected with so many diseases when Europeans came to North America?

A

Because the Europeans had built up immunity several pathogens over a long period of time but the Indigenous people had never been exposed to those diseases before. So the viruses spread very fast among Indigenous peoples.

33
Q

What are the three types of medicines used to treat pathogens?

A
  1. Traditional Medicines: Comes from natural sources, like aspirin which comes from the bark of the willow tree. Climate change may make it hard to discover new traditional medicines from plants.
  2. Vaccines: Substances that cause an immune response in the body, protecting the person against future infection.
  3. Antibiotics: Substances used to kill off bacteria. They do not work against viruses. A lot of antibiotics come from natural sources.
34
Q

What are four types of vaccines?

A
  1. Live, attenuated vaccine: Contains a living version of the microbe. Usually provides a strong, lifelong immunity after 1-2 doses.
  2. Inactivated vaccine: Contains microbes that have been killed. Provides immunity for a shorter period. Requires periodic booster shots.
  3. Subunit vaccines: Pieces of microbes are used for the vaccine. Immunity provided after multiple doses.
  4. Toxoid vaccines: Made up of inactivated toxins that bacteria produce. Needs periodic booster shots to keep immunity.
35
Q

What is ‘herd immunity’?

A

When a large enough share of the population is immunized that everyone is protected from a virus. Helps to prevent epidemics and pandemics.

36
Q

What is the risk of overusing antibiotics?

A

It can cause bacteria to become antibiotic resistant, leading to superbugs that are resistant to antibiotics. This why it’s important, if you get antibiotics, to take them as long as your doctor says so the bacteria doesn’t get a chance to become resistant.

grade 8 science (3 decks)

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