Biology Cell Notes

Cell theory

All living things are composed of cells and all cells come from preexisting cells

Diffusion

The movement of molecules or particles from an area of higher concentration to an area of lower concentration

3 domains of life:

Archaea, prokaryotes, and eukaryotes

Unicellular

Made up of 1 cell

Multicellular

Made up of multiple cells

Endosymbiotic theory

Organelles inside eukaryotic cells started as independent prokaryotic microbes that were “eaten” by a larger host cell and formed a permanent relationship where they both benefited each other

Magnification

The process of making an object appear larger than it is without changing its physical size

How many micrometers in 1 meter?

1,000,000

Resolution

The ability to distinguish between 2 objects

How does a light microscope work?

Visible light is passed through a specimen and then through glass lenses

How does an electron microscope work?

It focuses a beam of electrons through a specimen or onto its surface

How does a scanning electron microscope work?

Detailed architecture of cell surfaces

How does a transmission electron microscope work?

Study details of internal cell structure

What part of the microscope is this?

Head and it connects the lenses

What part of the microscope is this?

Nosepiece objective turret

What part of the microscope is this and what does it do?

Stage and it holds and stabilizes the specimen slide

What part of the microscope is this?

Iris diaphragm and it controls the light intensity

What part of the microscope is this and what does it do?

Illumination system and it is the light that goes up into the specimen

What part of the microscope is this?

Base

What part of the microscope is this and what does it do?

Eyepiece and it magnifies the specimen 10x

What part of the microscope is this?

Eyepiece tube

What part of the microscope is this and what does it do?

Objectives and they are the different levels of zoom, magnifies 4,10,40, or 100

What part of the microscope is this and what does it do?

Course focus and it moves the stage up and down and helps put the specimen in focus

What part of the microscope is this and what does it do?

Fine focus and it moves the stage in smaller increments to help put the specimen in focus

What part of the microscope is this?

Illumination intensity knob

What part of the microscope is this?

Condenser

What part of the microscope is this and what does it do?

Frame and it holds everything together

What happens to the surface area to volume ratio as organisms get larger?

Decreases

Why are cells small?

Because if there is not enough surface area, the nutrients can’t get to the cell fast enough

Examples of prokaryotes

Bacteria and archaea

Structure of prokaryotes

Small and structurally simple

Prokaryotes are the oldest cell type

True

Structure of eukaryotes

Larger and more complex

Examples of eukaryotes

Animals, plants, fungi, protozoa

What do plant cells have?

Cell wall, chloroplasts (some don’t), cellulose, central vacuole

What do animal cells have?

No cell wall or chloroplasts, smaller vacuoles

What do both plant and animal cells have?

Cytoplasm, all organelles

What happens in the endomembrane system?

Organelles work together to modify, package and transport lipids and proteins

What do both prokaryotes and eukaryotes have?

DNA, ribosomes, cytoplasms, cell membranes

What does the nucleus do?

Stores, protects, and manages the cells DNA

What does the mitochondria do?

Generates most of the cell’s chemical energy in the form of ATP

What does the chloroplast do?

Converts light energy into chemical energy

What does the lysosome do?

It is an enclosed sac of digestive enzymes that digests food and waste

What does the vacuole do?

Helps with storage

What does the central vacuole do?

Helps plant cells grow by absorbing water

What do the ribosomes do?

Make proteins

What does the cytoskeleton do?

Helps give the cell its shape

What does the golgi apparatus do?

Modifies, and ships proteins

What does the endoplasmic reticulum do?

Folds, modifies, and transports lipids and protein

Rough endoplasmic reticulum

Has ribosomes that make proteins

Smooth endoplasmic reticulum

Does not have ribosomes, detoxification of harmful chemicals

What is the sarcoplasmic reticulum?

A specialized smooth ER in muscle cells

What does the cell membrane do?

It controls what goes in and out of the cell and is semipermeable

What does the cytoplasm do?

Jelly like material that keeps organelles where they’re supposed to be

What does the cell wall do?

It protects the cells and provides skeletal support

What is cellular respiration?

The breaking down of nutrients and conversion of chemical energy to ATP