The Cell (Honors BIO)

Light microscopes (Definition and what image does it produce)

An instrument that uses visible light and glass lenses to magnify small objects. It produces a larger, inverted image of the specimen.

Transmission electron microscopes

Instrument that uses a beam of electrons that passes through a very thin specimen to create a highly magnified image. It produces a detailed, 2D image of the specimens internal structures.

Scanning electron microscope

An instrument that uses a beam of electron stop scan the surface of a specimen. It produces a highly magnified, detailed, 3D looking image of the specimens surface.

The three parts of the cell theory

1. All living things are made of one or more cells

2. The Cell is the basic unit of structure and function in living things

3. All cells come from pre-existing cells

Who discovered cells and how?

Robert hooke discovered cells in 1665 by using a microscope to look at thin slice of cork. He saw tiny box like structures and called them cells because they reminded him of small rooms.

Prokaryotic cells

Smaller and simpler; do not have nucleus or membrane bound organelles. Example Bacteria.

Eukaryotic cells

Larger and more complex; have nucleus and membrane-bound organelles. Example: plant, animal and human cells.

What do pro and eukaryotic cells have in common?

They both have DNA, ribosomes, cytoplasm, and a cell membrane

Plant cells

Have a cell wall, chloroplasts, and a large central vacuole. They are usually more rigid and rectangular in shape.

Animal cells

They don’t have cell walls or chloroplasts an dually have smaller vacuoles. They are more flexible in shape.

What do animal and plant cells have in common?

The both have a nucleus, cell membrane, cytoplasm, mitochondria, ribosomes, and other organelles

Nucleus

The control center of the cell. It contains the cells DNA and directs the cells activities, such as growth, reproduction, and making proteins

Nucleolus

Small structure inside the nucleolus. Its main job is to make ribosomes, which help the cell produce proteins.

Vacuole

Organelle that stores water, nutrients, and waste. In plant cells, the large vacuole also helps maintain pressure and support the cells shape.

Mitochondria

An organelle that produces energy for the cell. They break down nutrients to make ATP, the main form of usable energy cells need carry out their functions

Chloroplast

An organelle is found in plant cells that uses sunlight to make food through photosynthesis. It contains a green pigment called chlorophyll, which absorbs light energy.

Lysosome

an organelle that contains enzymes that break down waste, old cell parts, and harmful materials. It helps keep the cell clean and recycle useful materials.

Golgi apparatus

It modifies, sports, and packages protein and other materials so they can be transported to different parts of the cell or released outside the cells.

Endoplasmic Reticulum (smooth ER)

Creates lipids, helps detoxify harmful substances, and stores calcium. It does not have ribosomes attached to its surface.

Endoplasmic reticulum (rough ER)

Helps make and transport proteins. IT has ribosomes attached it its surface, which give it its rough appearance.

Ribosomes

Small structures that make proteins for the cell. They can be found floating in thee cytoplasm or attached to the rough ER

Cell wall

Rigid layer outside the cell membrane that supports an protects the cell. It also helps the cell keep its cheaper and is found in plant cells.

Cell membrane

A thin, flexible layer that surrounds the cell. It controls what enters and leaves the cell, helping maintain a stable environment inside.

Cytoplasm

jelly-like substance inside the cell that surrounds the organelles. It helps support the organelles and is where many of the cells chemical reactions take place.

Cytoskeleton

A network of protein fibers that supports the cell, maintains its shape, and helps move organelles and other materials within the cell.

Microtubules

Hollow protein fibers that are apart of the cytoskeleton. They help maintain the cells shape, move materials inside the cell, and help separate chromosomes during cell division.

Microfilaments

Thin protein` fibers that are part of the exoskeleton. They help support the cell, maintain its shape and allow the cell to move.

Structure and function of the plasma membrane

A thin flexible layer around the cell. It is made of two layers of fat molecules and proteins. It protects the cell and controls what enters and leaves the cell.

Permeable

A material allows a substance to pass through it. It lets things move in and out of the cell

Selectively permeable

The cell membrane allows SOME substances to pass through it but blocks the others. This helps the cell control what enters and leaves.

Impermeable

Nothing can pass through the material. An impermeable membrane blocks substances from entering or leaving the cell.

Concentration

The amount of a substance in a certain space. A high concentration means there is a lot of the substance, while a low concentration means there is less. Low = less sugar in water; high = more sugar in water

Concentration gradient

The difference in the amount of a substance between two areas. Substances tend to move from an area of high concentration to a low concentration.

What happens to concentrations after molecules move down a concentration gradient?

The high concentration decreases and thee low concentration increases. The difference gets smaller until they reach equilibrium

High gets lower - low gets higher - equilibrium

Passive transport

Moves molecules down a concentration gradient from high to low concentration without using energy. Types include diffusion, osmosis, and facilitated diffusion.

Active transport

Moves molecules up against the concentration gradient, from low to high concentration, and requires energy (ATP). Types include protein pumps, endocytosis, and exocytosis.

Is there a net total change in concentration?

No there is no net change in concentration because molecules move equally in both directions.

Do molecules continue to move across the membrane. What directions?

At dynamic equilibrium, molecules continue to move in both directions across the membrane.

Homeostasis

The process of maintaining a stable internal environment in a cell or organism, even when conditions change.

Cell

Basic unit of life . All living things are made up up one or more cells

Tissue

A group of similar cells that work together to perform a specific function

Organ

a group of different tissues that work together to perform a specific function

Organ system

A group of organs that work together to perform a specific function.

Organism

An individual living thing made up of one or more cells

Diffusion

The natural spreading out of particles from an area of high concentration to an area of lower concentration.

Osmosis

the movement of water molecules through a special barrier into an area with more dissolved particles to balance the concentrations on both sides

Facilitated diffusion

the passive movement of molecules or ions across a cell membrane with the help of specific transport proteins

Pumps

use cellular energy (like ATP) to move ions actively against their gradient

Endocytosis

The process of taking materials into the cell

Exosytosis

The release of large amounts of material from a cell.