Cells and microscope study guide

Robert Hooke

Robert Hooke

-First to describe cells -viewed thin slices of cork and compared them to cells in a monastery

Anton van Leeuwenhoek

-Observed cell organisms -"Little animalcules" -First to observe a red blood cell and a sperm cell

Robert Brown

Named the nucleus

A compound light microscope

A.) Two lenses (ocular and objective) B.) Specimen must be transparent

Ocular

-The eye piece -Magnifies the image

Body Tube

Holds the lenses

Nosepiece

rotates the objectives/lenses

Stage

The platform for the slide

Stage Clips

holds slide into place

Diaphragm

Controls the amount of light passing through the specimen

Mirror/light source

• lights the specimen so its easier to observe

• (Mirror reverses the image of the specimen)

Arm

Used to carry the microscope

Base

Supports the microscope

Coarse Adjustment Knob

• Used for preliminary focusing

• NEVER used on high power

Fine Adjustment Knob

used to focus on high power, and to fine tune low power

High power objective has a magnification of 10

This objective has a magnification of 100x (this is the max magnification)

Low power objective

This objective has a magnification of 10x (Minimum magnification) (Scanning objective - has a magnification of 4x)

Magnification power is equal to

the product of the ocular lens times the objective

resolution

Ability to distinguish between two objects very close together

what limits the resolving power of the light microscope?

The properties of light

electron microscope

uses a beam of electrons instead of light to get a greater resolution and magnification

Dissecting microscope

used for viewing opaque specimens provides a 3-D view does not reverse the image

Phase Contrast Microscope

provides contrast without stains

ultracentrifuge

separates organelles by spinning them in a test tube denser parts sink to the bottom of the test tube

The cell is

the basic unit of life

The cell theory

• All organisms are made up of one or more cells

• These cells working individually, or together in tissues or organs, preform all life functions -All cells come from pre-existing cells.

Exceptions to the cell theory

• The first cell could not have come from a pre-existing cell

• Viruses, which are NOT cells have hereditary material and can reproduce

• Organelles such as mitochondria and chloroplasts have DNA and can reproduce

prokaryote

-Do not have structures surrounded by membranes -Few internal structures -one celled organisms (like bacteria) -look like tampons

eukaryote

-Contain organelles surrounded by membranes -most living organisms

Cell organelles

Organelles are small specialized structures that carry out life functions within cells

Plasma cell membrane

-regulates the movement of materials into or out of the cells -semi-permeable -selectively-permeable (like a door it can open and close) -composed of a lipid bilayer with embedded proteins -it is fluid meaning it is flexible and are able to move within the membrane

cytoplasm

-Jelly like environment of the cell (mostly H2O)

cyclosis

Movement of the cytoplasm (transports materials within the cell)

Nucleus

-Controls cell activites -surrounded by nuclear membrane -contains genetic material (DNA and RNA) -Involved in reproduction

Nucleolus

-Dense region in the nucleus -Involves in the synthesis of ribosomes

Mitochondrion

-Site of cellular respiration -Produces energy (ATP) for metabolism

Golgi Complex / Apparatus

Synthesis, packages

ribosomes

Site of protein synthesis

Endoplasmic Reticulum (ER)

-Forms passages throughout the cell for intracellular transport -Connects the nuclear membrane to the plasma membrane

Rough ER

covered in ribosomes

Smooth ER

No ribosomes

lysosome

-contains digestive enzymes -breaks down damaged organelles or pathogens

Vacuole

Space in a cell surrounded by a membrane

Food vacuole

Stores food to be digested

Contractile vacuole

helps maintain water balance within a cell

Centrioles

-Only in animal cells -play a role in cell division

Chloroplast

-Only in plant cells -Preform photosynthesis

Cell wall

-Only in plant cells -non-living structure that surrounds, supports and protects the cell -made of cellulose (a polysaccharide)

Cover slips are used for

wet mounts

what is the magnification of a 20x objective

200x

What substance is added to make the details of a specimen's cell structure more visible

methylene blue

What is a compound microscope created for

a cell

When is the field of vision largest

under low power

A group of non-photosynthetic prokaryotes would all have

cell walls

which two organelles work together to support animal cells

cell membrane and cytoplasm

which cell structure is energy extracted from nutrients

mitochondrion

what do animal cells and bacteria cells have in common

DNA and Ribosomes

An ameba is a single-celled, heterotrophic organism. in order to meet its energy needs it directly relies on the interaction of which cell structures

the cell membrane and mitochondria

Protein synthesis is accomplished primarily by the interaction of which two cells structures

nuclei and ribosomes

The presence of which cell structure helps classify an organism as eukaryotic

nucleus

One primary function of the cell membrane is

regulating the flow of simple sugars into or out of the cell

A white blood cell ingests, and then digests, a number of bacteria. which cell organelles were directly responsible for the digestion of bacteria

lysosome

In single-celled organisms, materials are stored primarily in

vacuoles

Single-celled organisms are able to maintain homeostasis, even though they lack higher levels of organization such as organs and organ systems because

cell structures work together to maintain homeostasis in single-celled organism