Science - Grade 8 > Life System > Flashcards

Life System Flashcards

Grade 8 Science (63 cards)

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1
Q

What are the largest cells?

A

Nerve cells

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2
Q

Robert Hooke believed that cells only existed in…

A

Plants and fungi

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3
Q

What name did Anton van Leuwenhoek give to single-celled organisms?

A

Animalcules

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4
Q

Describe Spontaneous Generation?

A

Making living things from non-living things

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5
Q

List the 5 components of the Current Cell Theory.

A
  • All organisms are composed of one or more cells.
  • The cell is the basic unit of all living things.
  • All cells are produced by the division of pre-existing cells.
  • Energy flows inside cells.
  • Cells contain DNA which determines the organisms’ characteristics.
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6
Q

What are the names of the two main types of cells?

A

Prokaryotic and Eukaryotic.

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7
Q

What are the 4 main function of cells?

A
  • Cells work together to keep living things alive.
  • Get rid of wastes.
  • Repair and grow.
  • Get energy from food/sun.
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8
Q

What are animal cells?

A

Animal cells are eukaryotic (nucleus in a cell membrane). They are only found in animals and not plants.

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9
Q

What are the functions of the Cytoplasm?

A

It is a gel like substance that holds the organelles together. It is where many chemical reactions occur.

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10
Q

What are the functions of the Cell Membrane?

A

It keeps the organelles together. It controls what comes into and what leaves the cell.

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11
Q

What are the functions of the Nucleus?

A

The nucleus contains DNA that tells the cell what to do. Usually, there is only 1 per cell and is spherical in shape.

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12
Q

What are the functions of the Mitochondria?

A

The mitochondria are the powerhouse of the cell. They make energy from the food you eat. Cells that use more energy contain more mitochondria.

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13
Q

What are the functions of the Endoplasmic Reticulum?

A

It is the subway of the cell. It is a network of transportation tubes that moves substances around the cell. It is where some proteins are made.

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14
Q

What are the functions of the Golgi Body?

A

The Golgi Body works with the E.R. to collect and process materials to be used by or removed from the cell. It creates mucous for your stomach and intestines.

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15
Q

What are the functions of the Vacuoles?

A

It is the trash can of the cell. It contains unwanted substances that are to be removed from the cell. Many are found within a cell.

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16
Q

What are the functions of cells?

A
  • Cells work together to keep living things alive.
  • Get rid of wastes.
  • Repair and grow.
  • Get energy from food/sun
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17
Q

What are the differences between plants and animals?

A

Animal cells are only found in animals. Plant cells are only found in plants.
Plant cells are often larger than animal cells. Animal cells are irregularly/spherical shaped and plant cells are rectangular in shape. Plant cells have additional organelles (cell wall, chloroplasts, large central vacuole).

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18
Q

What organelles are common in both plant and animal cells?

A

Cytoplasm, cell membrane, nucleus, mitochondria, Endoplasmic Reticulum, Golgi bodies, vacuoles

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19
Q

Which organelles are found only in plant cell?

A

Chloroplasts, larger central vacuole, cell wall

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20
Q

What are the functions of the Large Central Vacuole?

A
  • Temporarily holds wastes
  • Helps maintain an internal pressure
  • Keeps the leaves and stems large and firm
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21
Q

What are the functions of the Cell Wall?

A
  • Very hard structure made of cellulose
  • It provides strength to the cell as well as protection
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22
Q

What are the functions of the chloroplasts?

A
  • It makes food (glucose) through photosynthesis
  • It contains chlorophyll which allows them to absorb the energy from the sun
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23
Q

Explain photosynthesis in plants.

A

Chloroplasts take carbon dioxide (CO2) and water (H2O) from the environment and light energy from the sun to create glucose(CH2O) and oxygen (O2).

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24
Q

What is the main purpose of photosynthesis?

A

The main purpose is to create sugar for food and oxygen for animals.

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25
What would happen if photosynthesis stopped in all plants?
Almost all living things on earth would eventually die.
26
What are the 3 main types of unicellular organisms?
Bacteria, Protozoa, and Unicellular Fungi
27
Name 1 helpful kind of bacteria and 1 harmful type of bacteria.
Good – bacteria in your intestine that help you break down food Bad – E. Coli, listeria, and salmonella
28
List 3 different characteristics of protozoa.
They live in water They can move and hunt for food They range in size from 10 mim to 20 cm.
29
What are 1 characteristics of unicellular fungi? What benefits do unicellular fungi have on humans?
The most common unicellular fungi is yeast. Some forms of yeast are used to make beer and bread. They are used in cancer research because they are easy to grow.
30
List 3 different characteristics of amoebas.
They can alter their shape They can be found in the protozoa, unicellular fungi, algae, and animal groups They can be seen with a light microscope
31
What is phagocytosis?
This is how unicellular organisms feed. The organisms extend their pseudopods (tentacles) to surround their food. The pseudopods connect and brings the food inside the organism for digestion.
32
How do unicellular organisms move?
They move by using their pseudopods Some have flagella (hair-like structures) that move rapidly
33
How do unicellular organisms reproduce?
Asexual reproduction—they duplicate everything inside themselves and split in two
34
How do unicellular organisms exchange gases (breathe)?
They breathe through diffusion. Diffusion is the movement of substances from an area of high concentration (many) to an area of low concentration (not much).
35
How do multicellular organisms feed?
Fungi – break down food outside of themselves and then absorb the nutrients Plants – Photosynthesis Animals – they consume food through their mouth and digest the food internally
36
How do multicellular organisms move?
Plants – they cannot move by themselves Animals – they walk on 1 or more limbs
37
What 2 ways do multicellular organisms reproduce?
Fungi – asexual reproduction -> make clones of themselves Plants and animals -> sexual reproduction -> 2 organisms make 1 organism
38
What are gametes?
Gametes are the cells produced by the parents and then are fertilized to produce an offspring.
39
Explain gas exchange in multicellular animals.
Algae – diffusion Rest of the animals – O2 (oxygen) is sent through the nose or mouth and into the lungs (alveolus). From there O2 is sent into the blood stream. CO2 is removed from the blood and exhaled through the mouth or nose. Fish use gills to get oxygen from the water.
40
Explain gas exchange in multicellular plants.
Algae – diffusion Water plants – water passes over the plant and provides CO2. The plant then releases oxygen into the water Land Plants – CO2 enters and O2 exits through tiny holes in the leaves called stomata
41
Why are cells specialized?
Since multicellular organisms are so complex, we need to have cells that just do certain things really well.
42
List the cell organization from least to most complex with a brief explanation of each one.
Cell – the basic unit that performs a certain function (muscle cell) Tissue – a collection of cells performing a certain function (stomach lining) Organ- two or more tissue types working together (stomach) Organ System – a group of organs working together (digestive system) Organism – many different organ systems working together (human)
43
What are 2 functions of muscle cells?
Muscles use a lot of energy and have many mitochondria. They help your body move.
44
What is the main function of nerve cells?
Nerve cells or neurons send signals around the body using electricity.
45
What are the 4 main types of tissues? Provide an example for each type?
Epithelial – skin, lining of organs Connective – bone, tendons, blood Muscle – cardiac, skeletal, Smooth (muscle) Nerve – brain, nerves
46
What is an organ? Provide 1 example of an organ.
A group of tissues working together to perform a specific job (heart).
47
What is an organ system? Provide 1 example of an organ system.
A collection of organs working together to perform a specific function (circulatory system).
48
What is the purpose of the cell membrane?
It keeps the cell organelles together. It controls what comes into and what leaves the cell.
49
Explain the purpose of a phospholipid.
It is a special kind of fat. It’s head loves water and its tails hates water.
50
What is a semi-permeable membrane?
It is a membrane that allows some things to enter (sugar, fat, protein, oxygen, salt) and others things are not allowed to enter (too big, water soluble).
51
Why do cells make protein doors?
This allows substances to pass through the cell membrane that normally could not pass through the cell membrane.
52
Explain diffusion.
Molecules move from an area high (many) to low (not much) concentration.
53
What is osmosis?
The diffusion of water across a membrane.
54
What are the 3 different types of osmosis?
Hypertonic, Hypotonic, and Isotonic
55
What is a hypotonic solution? What happens to cells in a hypotonic solution?
When there is more water outside of the cell than inside of the cell. The cells will swell and can burst.
56
What is a hypertonic solution? What happens to cells in a hypertonic solution?
When there is more water inside of the cell than outside of the cell. The cells will shrink and could perish.
57
What is an isotonic solution? What happens to cells in an isotonic solution?
When there is no difference in water concentration, in the cell and outside of the cell. The volume of the cell does not change.
58
What is blood?
Blood is the fluid that flows throughout your body carrying oxygen and nutrients.
59
What are the four different blood types?
Type A, Type B, Type AB, Type O
60
How do you get your blood type?
You inherit your blood type from your parents. When you were conceived, each one of your parents gave you an allele that produces your blood type.
61
How can someone have Type AB blood?
Both of your parents are Type AB or one parent is Type A and the other parent is Type B.
62
Why is it important to know your blood type?
Not all blood types can be combined. If someone receives a transfusion of an incompatible blood type they could possibly die.
63
Why are Type O people called universal donors?
Type O blood does not have any antigens. That means you cannot pass anything on to hurt them.
Science - Grade 8
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