Cells & Systems Flashcards
Cells & Systems covers all the material which we have learned within the second unit of grade 8 science.
What does biotic mean?
Living.
What does abiotic mean?
Non-living.
What are the characteristics of living things? (6)
- Made of cells.
- Need energy.
- Grow and develop.
- Respond to the environment.
- Reproduce.
- Adaptations.
What do you have to keep in mind about the characteristics of living things when it comes to biotic and abiotic features?
All living things, or organisms, have all six characteristics. Non-living things may have some of these, but not all.
What is the basic unit of life?
Cells. All living things are made up of them. They perform all the processes that life depends on.
Are abiotic things made up of cells?
No, unless the material was alive at one time.
Provide an example of a non-living feature in which cells can be found. Why is that the case?
A piece of wood; because the wood came from a tree that was once alive.
Define energy.
The ability to make things move or change.
How do plants and animals differ in how they get their energy?
Plants use the energy from the sun, whereas animals get their food from the environment around them.
Define nutrient.
Nutrients are substances that provide the energy and materials that organisms need.
What do plants and animals use nutrients for? (3)
- Grow.
- Develop.
- Reproduce.
Where do plants and animals obtain nutrients from? (2)
- Food.
2. The environment.
Define stimulus.
Anything that causes a response in an organism.
What is an example of a stimulus?
If you are crossing the street, and a car is coming towards you, you will probably jump out of the way. In this situation, the car is the stimulus, and jumping out of the way is the response.
Is growth getting taller? Provide an example.
Yes, but that’s not all. It’s also changing in structure.
For example, once you reach a certain height, you will not grow any taller. But your skin cells will continue to replace themselves.
Define adaptation.
A characteristic that allows an organism to live in its environment.
Provide an example of adaptation.
A cactus has spines to stop animals from eating it.
What’s the difference between a structure and a function?
Structures are different body parts. Functions are what the structures are good for.
What organs are part of your circulatory system? (5)
- Heart.
- Arteries.
- Veins.
- Capillaries.
- Blood.
What are the functions of the circulatory system? (4)
- Transport oxygen, food, and other substances throughout the body.
- Transports some wastes to other organs for elimination.
- Defends the body against diseases.
- Connects all other organ systems.
What organs are part of your respiratory system? (6)
- Nose.
- Mouth.
- Trachea.
- Diaphragm.
- Bronchi.
- Lungs.
What are the functions of your respiratory system? (2)
- Transport oxygen from the outside air to the blood.
2. Transport carbon dioxide from the blood to the outside air.
What organs are part of your digestive system? (9)
- Salivary glands.
- Mouth.
- Esophagus.
- Stomach.
- Liver.
- Pancreas.
- Gall bladder.
- Small intestine.
- Large intestine.
What are the functions of your digestive system? (1)
- Breaks down food pieces into much smaller pieces (particles) so they can be absorbed and transported throughout the body.
What organs are part of your nervous system? (4)
- Brain.
- Spinal cord.
- Nerves.
- Eyes, ears, and other sensing organs (hands, nose, etc.)
What are the functions of your nervous system? (2)
- Coordinate and control the actions of all organs and organ systems.
- Detect, process, and respond to changes in external and internal environments.
What organs are part of your excretory system? (5)
- Kidneys.
- Bladder.
- Lungs.
- Skin.
- Liver.
What are the functions of your excretory system? (1)
- Removes chemical and gaseous wastes from the blood.
What organs are part of your skeletal system? (2)
- Bones.
2. Cartilage.
What are the functions of your skeletal system? (2)
- Provide a moveable support frame for the body.
2. Protect soft-tissue organs such as the heart and lungs.
What organs are part of your muscular system? (2)
- Muscles.
2. Tendons.
What are the functions of your muscular system? (2)
- Move bones.
2. Move organs that contain muscle tissue (such as the heart and stomach).
What organs are part of your integumentary system? (1)
- Skin.
What are the functions of your integumentary system? (2)
- Protects the body’s internal environment from the external environment.
- Senses pain, pressure, and temperature.
What are your organ systems called? (8)
- Circulatory system.
- Respiratory system.
- Digestive system.
- Nervous system.
- Excretory system.
- Skeletal system.
- Muscular system.
- Integumentary system.
What is the smallest known functioning unit of life?
A cell.
What do cells make up?
cells –> tissues
tissues –> organs
organs –> organ systems
Define organelle.
A specialized structure that carries out specific functions found within a cell.
What are the parts of a cell? (7)
- Nucleus.
- Mitochondria.
- Cell membrane.
- Vacuoles.
- Cytoplasm.
- Cell wall.
- Chloroplasts.
Which organelles are found in a plant cell but not in an animal cell?
Which organelle does an animal have several of, but a plant only has one of?
A cell wall and chloroplasts are only found within plant cells.
Animal cells have several small vacuoles, while a plant cell has one large one.
What is the function of the nucleus?
Directs all cellular activities such as movement, growth, and other life functions.
What is the nucleus also known as?
A “command centre”.
What is the function of the mitochondria?
Chemical reactions occur here. They convert the energy the cell receives into a form it can use.
What are the mitochondria also known as?
The “powerhouses” of the cell.
What is the function of the cell membrane?
Lets needed materials in and waste materials out.
What is the cell membrane also known as?
A “controllable gateway”.
What is the function of the vacuole(s)?
Nutrients, water, or other substances can be stored here by the cell.
What is the vacuole also known as?
The “storage room”.
What is the function of the cytoplasm?
Contains the nutrients required by the cell to maintain its life processes.
What is the cytoplasm also known as?
The “kitchen” of the cell.
What is the function of the cell wall?
It provides strength and support.
What is the cell wall also known as?
The “frame” of the cell.
What is the function of chloroplasts?
Carry out photosynthesis, converting the sun’s energy into food for the cell.
What are chloroplasts also known as?
The “solar panels” of the cell.
Define multicellular.
An organism that is made up of two or more cells.
What are examples of multicellular organisms?
Plants and animals.
Define unicellular.
An organism that is made up of one cell.
What are two examples of unicellular organisms?
Most micro-organisms, such as mycoplasma, amoeba, and paramecium. Diatoms are single-celled plants.
What is an organism called that is made up of two or more cells?
Multicellular.
What is an organism called that is made up of one cell?
Unicellular.
There is a tendency to consider unicellular organisms as ___.
Simple.
Why is there a tendency to consider unicellular organisms as simple?
Because they lack the tissues and organs of more advanced creatures.
Is the idea that unicellular organisms are simple right? Why or why not? (5)
No. A single-celled organism can do most things that we need trillions of cells to do:
- Eat.
- Move.
- React to stimuli.
- Get rid of waste products.
- Reproduce.
What is an amoeba?
Amoebas are common unicellular organisms that live in water.
How does an amoeba survive?
They move around using foot-like projections called pseudopods. They extend a pseudopod and the cytoplasm streams into it. Amoebas also use these pseudopods to capture food. The ends of the pseudopods fuse together and create a vacuole around the food particle. The food in the vacuole is digested and absorbed into the cytoplasm.
Define pseudopod.
They are foot-like projections that amoebas use to move and capture food.
How does a paramecium survive?
Paramecium move swiftly through the freshwater where they live. They are covered in hair-like structures called cilia, which move back and forth like oars to move them through the water. Cilia also help them gather food. On one side of the cell is a channel called an oral groove. It is lined with cilia, which sweep food to the bottom of the groove. There, the food enters a food vacuole, which moves into the cytoplasm, and the food inside is digested.
Define cilia.
They are hair-like structures that move back and forth like oars to move paramecium through the water and help them gather food.
Define oral groove.
A channel that is found on one side of the cell of a paramecium. It’s lined with cilia, which sweep food to the bottom of the groove.
Define diffusion.
Moves particles from an area of high concentration to an area of low concentration. It’s a “balancing out” or “evening out” process that continues until the concentration of particles is the same everywhere.
When it comes to diffusion, how does the cell membrane act? What is this called?
Like a filter with extremely tiny openings that allow some particles to pass through. This is called selectively permeable.
Define selectively permeable.
The cell membrane allows the particles of some substances to pass through it, but not others. Therefore, we say that the cell membrane is selectively permeable.
Why are the openings in the cell membrane so small? (2)
- To keep the cell’s cytoplasm and organelles inside.
2. To keep particles of most substances in the cell’s external environment out.
Define osmosis.
The diffusion of water through a selectively permeable membrane.
What is the difference between diffusion and osmosis?
Osmosis is specifically the diffusion of water.
What does the survival of a cell depend on?
Its ability to balance water uptake and loss.
What happens if a cell does not have enough water?
It will shrink.
What happens if a cell has too much water?
It will swell.
What happens if a PLANT cell does not have enough water?
The cell shrinks inside the cell wall, causing the cell to lose its stiffness.
Who are the three people who are famous for developing microscopes? Where are they from? When?
- Hans Lippershey (Germany, late 1500s)
- Zacharas Janssen (Netherlands, late 1500s)
- Galileo Galilei (Greek, early 1600s)
What identifies a compound light microscope? (2)
- Multiple lenses.
2. A light.
What kind of microscope has multiple lenses and a light?
A compound light microscope.
What are the parts of a compound light microscope? (11)
- Eyepiece.
- Coarse adjustment knob.
- Fine adjustment knob.
- Revolving nosepiece.
- Objective lenses.
- Stage.
- Stage clips.
- Diaphragm.
- Lamp.
- Arm.
- Base.
What does the eyepiece do?
Contains the lens that magnifies.
Which part of the microscope contains the lens that magnifies?
The eyepiece.
What does the coarse adjustment knob do?
Moves the stage up/down to focus on the object to produce a clear, sharp image.
Which part of the microscope moves the stage up/down to focus on the object to produce a clear, sharp image?
The coarse adjustment knob.
What does the fine adjustment knob do?
Brings the object into sharper focus.
Which part of the microscope brings the object into sharper focus?
The fine adjustment knob.
What does the revolving nosepiece do?
Holds the three objective lenses.
Which part of the microscope holds the three objective lenses?
The revolving nosepiece.
What do the objective lenses do?
Provide different strengths of magnification.
Which part of the microscope provides different strengths of magnification?
The objective lenses.
What does the stage do?
Supports the slide that holds the object you want to view.
Which part of the microscope supports the slide that holds the object you want to view?
The stage.
What do the stage clips do?
Hold the slide firmly on the stage.
Which part of the microscope holds the slide firmly on the stage?
The stage clips.
What does the diaphragm (of a microscope) do?
Has different-sized holes that let different amounts of light pass through the object.
Which part of the microscope has different-sized holes that let different amounts of light pass through the object?
The diaphragm.
What does the lamp do?
Supplies the light that passes through the object.
Which part of the microscope supplies the light that passes through the object?
The lamp.
What does the arm (of a microscope) do?
Allows you to carry the microscope securely.
Which part of the microscope allows you to carry the microscope securely?
The arm.
What does the base do?
Serves as a foundation for the rest of the microscope.
Which part of the microscope serves as a foundation for the rest of the microscope?
The base.
Why are unicellular organisms tiny?
There are limits to how large they can grow. One of the reasons involves diffusion and osmosis. These vital processes work well only over very short distances. Your body cells also reproduce to repair tissues that get damaged.