Grade 8 Science Section 2

explain the 3 parts of cell theory

The cell is the basic unit of life
All cells come from pre-existing cells
All living things are made of one or more cells.

Plant Cells

A plant cell is a eukaryotic cell with a cell wall, chloroplasts, and a large central vacuole that helps the plant make food and stay firm.

Animal Cells

An animal cell is a eukaryotic cell without a cell wall or chloroplasts, usually with a small vacuole, that carries out all the functions needed for the animal to live.

Unicellular organisms

Organisms made up of 1 cell

Multicellular Organisms

Organisms made of multiple cells

Who made cell theory

Theodor Schwannn and Matthias Schleiden

Whats does latin cell translate to?

Small room

what is an organelle?

A specialized part of the cell that has a specific function. Organelles do a job for the cell they are in.

Nucleus

The nucleus is the command center of the cell that stores the cell’s DNA

Cell Membrane/Plasma Membrane

The cell membrane provides protection for the cell. It provides a fixed environment inside the cell that contains the other organelles. 

Cell Wall

The cell wall surronds the cell membrane and provides the cell with shape, support, and protection.

Chloroplasts

Only found in plant cells, responsible for photosynthesis. Chloroplasts take in light energy and convert into chemical energy via the photosynthesis process.

Vacuole

Vacuoles are sacs that take in waste products like harmful toxins and get rid of these waste products. Often the waste is water so the vacuole works to maintain the balance of water inside and outside the cell.

Mitochondria

The mitochondria is the powerhouse of the cell that works to transform molecules like glucose and turn them into energy the cell needs.

Cytoplasm

Gel like fluid inside the cell that is responsible for holding the organelles and protecting them from damage.

Endoplasmic Reticulum

Prepares proteins and lipid (fat) molecules for use inother places inside and outside the cell.

Golgi Apparatus

Transportation system for the cell

Lysosome

Contains digestive enzymes and breaks down excess or worn out cell parts

Cell

Cells are the smallest unit that can live on their own and that make up all living organisms and the tissues of the body. Cells are the basic building blocks of all living things.

Chromosome

A chromosome is a thread-like structure inside the nucleus of cells that contains the genetic information for an organism

What are things that are plant-cell specific

-Chloroplasts

-A cell wall

-A large central vacuole

-A definite shape that is usually rectangular or cubic
-A nucleus on the side
-Size of 10-100 micrometers

What are things that are animal cell specific?

-No cell wall
-No Chloroplasts
-Many small vacuoles
-An irregular shape that is round

-A nucleus in the center
-Are between 10-30 micrometers

What are the differences between plant cells/animal cells

Animal cells have no cell wall or chloroplasts, animal cells have many small vacuoles but plant cells have a large central vacuole, shape, nucleus position, and size

What are similarities between plant/animal cells?

-Both have a nucleus, mitochondria, e.r, golgi apparaturs, lysosoms, cell membrane, and contain cytoplasm

List all organelles in cells

cell membrane, cell wall, chloroplast, nucleus, chromosome, vacuole, cytoplasm, endoplasmic reticulum, mitochondria, lysosome, golgi body

What size of cell is more effiecient at transporting substances in and waste products, Large Or Small? Explain Why:

The small cell is more effecient because it would have a greater surface area relative to its volume so substances can leave and enter more effeciently.

Why is it not possible for a single-celled amoeba to grow as large as you?

It is a single celled organism. If it were to grow as large as a person its surface area relative to its volume would be much too small to allow the cell to transport material that it requires or must get rid of across its membrane

What is the word formula for photosynthesis?

Carbon Dioxide + Water+ Light Energy = Carbohydrates + Oxygen

What is the word formula for cellular respiration?

Oxygen+ Carbohydrates = Carbon Dioxide + Water + Energy

Why is photosynthesis important?

We can not make our own food (glucose, energy), we must get our food from plants. Plants are the first step in the food chain. The oxygen released during photosynthesis is necessary for all living things.

What is cellular respiration?

Cellular respiration is the process in which simple food substances (carbohydrates) are broken down, and the energy they contain is released. Occurs in the mitochondira because energy is produced in the mitochondria.

Permeable membrane

Allows all substances in

Impermeable Membrane

Lets NO substances in

Semi-permeable

Allows some but not all substances in.

What is the best type of membrane?

Selective permeable because it only keeps things that are good for the cell.

Diffusion

The process where molecules of a substance move from an area of high concentration to an area of low concentration

Osmosis

The passage of water from an area of high water concentration to an area of low water concentration.

Active Transport

Active transport is the passage of molecules against the concentration gradient, in other words from an area low concentration to high concentration

List something only about diffusion

How oxygen leaves a leaf

List something only about osmosis

Involves water only
How water keeps plants turgid

List something about Active Transport

Requires Energy
Against a concentration gradeint

List a similarity between diffusion and osmosis

Is Passive
High to Low Concentration

List a similarity between diffusion, osmosis, and active transport

Occurs in nature
Movement of particles

List similarities between diffusion and active transport 

Involves transport of solutes

List similarities between osmosis and active transport 

Needs a semi-permeable membrane

List examples of unicellular organisms

Bacteria
Protozoa
Phytoplankton
Unicellular Algae
Unicellular Fungi
Amoeba
Paramecium

List examples of multicellular organisms

Plants/Flowers, Animals, Humans.

Cell Specialization

Cells that are designed to do a specific job

Advantages of cell specialization

Live in a wide variety on environments
Are able to grow large
Can obtain energy from a whole variety of food
Cells specializied and therefore work more effiecently

Disadvantages of cell specialization

Each cell is dependent on other cells to survive (can only do 1 job)
Most multicellular organisms have cells that can become anything

4 main differences between active transport/diffusion

Active transport uses energy but diffusion does not
Active transport uses carrier proteins but diffusion does not
Diffusion occurs from high to low concentration but active transport occurs from low to high concentration
Active Transport allows movement of particles too large to fit through the cell membrane by membrane transporters