BIOLOGY 1 1st Sem Midterms Summary

COMPOUND MICROSCOPE

Combination of lenses that produces a highly magnified image of microscopic living entities and other details; has more than one lens and its own light source

MICROGRAPH

Image produced by a microscope

MAGNIFICATION

Measure of an optical instrument for an object to appear larger

RESOLUTION

Clarity of an image

VIDEO MICROSCOPY

Using image processing to view or photograph microscope images on a TV or computer screen

COMPOUND MICROSCOPE (KIND)

Commonly used in schools, can magnify objects up to 2,000x, used to examine cells and thin sections of tissues, uses sunlight or artificial light as its light source

PHASE-CONTRAST MICROSCOPE

Used to examine transparent specimens, such as unstained cells

STEREOSCOPIC / DISSECTING MICROSCOPE

Has 2 eyepieces (binocular head), providing a three-dimensional (3D) view, used for biological dissections and entomology

ELECTRON MICROSCOPE

Uses beams of electrons instead of light, can magnify objects up to 10,000,000x, electron micrographs are usually black and white

TRANSMISSION ELECTRON MICROSCOPE (TEM)

Used to study internal structures of cells, usually cut into very thin sections

SCANNING ELECTRON MICROSCOPE (SEM)

Used to examine three-dimensional surface structures and shapes of specimens

ELECTRON MICROSCOPE TYPES

Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM)

FLUORESCENCE MICROSCOPE

Uses fluorescent dyes that glow when exposed to specific wavelengths of light, used to study the location of specific molecules or organelles inside cells

CONFOCAL SCANNING MICROSCOPE

Used to examine three-dimensional structure of cells or organelles without physically cutting the specimen into sections, uses laser beams to scan across the specimen, produces detailed sections that can be combined to create a 3D image

FOOT or BASE

Supports the entire weight of the microscope

STAGE CONTROL

Stands on the base and supports the stage, and moves the stage clips in horizontal and vertical positions

ARM

A curved, strong structure used to handle the microscope

MECHANICAL STAGE

Flat, rectangular plate connected to the lower end of the arm and the specimen is placed here

STAGE CLIP

Holds the slide securely in its position and keeps it stable

DIAPHRAGM

Controls and adjusts the intensity of light that passes

IRIS DIAPHRAGM

Controls the light with an adjustable opening

DISC DIAPHRAGM

Controls light using different-sized holes

CONDENSER

Gathers and focuses light from the illuminator onto the specimen

NOSEPIECE

Rotating turret that holds multiple objective lenses

BODY TUBE or HEAD

Upper part of the arm comprises a hollow and tubular structure

FINE ADJUSTMENT KNOB

Smaller knob that makes sharp and small focus adjustments (1)

COARSE ADJUSTMENT KNOB

Larger knob that moves the tube/stage up and down and large movement/rough focusing (2)

CONDENSER FOCUS KNOB

A knob that moves the condenser vertically to control the focal concentration of light.

DIOPTER ADJUSTMENT

Adjusts focus for differences between your eyes

APERTURE

Hole in the middle of the stage that allows light to reach the specimen

POWER SWITCH

Turns the illuminator on and off

LIGHT INTENSITY CONTROL

Changes the intensity of the light source

INCLINATION JOINT

Pivoting mechanism that allows the upper assembly to tilt backwards

RACK STOP

Safety feature that limits how high the stage rises to prevent the objective from hitting the slide

THUMB SCREW

Attaches the microscope head to the arm

EYEPIECE or OCULAR

Located at the top of the body tube; the lens you look through to view the specimen (Typically 10x power, though 15x & 20x exist)

ILLUMINATOR

Light source of the microscope that provides light to illuminate the specimen (Older microscopes may use a mirror to reflect light)

OBJECTIVE LENS

Lenses located at the nosepiece that magnify the specimen at different magnification levels (4x, 10x, 40x, 100x)

4X (SCANNING OBJECTIVE)

Shortest and lowest, used to locate the specimen

10X (LOW POWER OBJECTIVE)

Middle sized and magnification, used for general overview

40X (HIGH POWER OBJECTIVE)

Longest and highest magnification power, used for detail structure viewing

100X (OIL IMMERSION OBJECTIVE)

Requires a drop of oil to be placed for optical performance by reducing light refraction, used for tiny specimens like bacteria

What happens when magnification is higher?

Higher magnification results in a greater amount of light and detail, but a smaller field of view

TOTAL MAGNIFICATION FORMULA

Eyepiece lens magnification × Objective lens magnification

MAGNIFICATION OF AN IMAGE FORMULA

Total magnification power × Size of the specimen

MICROSCOPE SLIDES

Thin sheet of glass used to hold the specimen in place

COVER GLASS

Avoids contact of the specimen with the lens and holds it in place

SPECIMEN (MICROSCOPY)

Piece or portion of a sample selected for examination

CELL

Basic biological unit of all known living organisms

ROBERT HOOKE

Devised one of the earliest microscopes using a thin slice of cork; called porous structures "cellulae" (Latin for "small room"); first to be credited with publishing the first description of a cell in 1666

Robert Hooke was first to be credited with publishing the first description of a cell in this year

1666

"cellulae"

Latin for "small room"

ANTONIE VAN LEEUWENHOEK

First to study magnified cells; devised his own simple microscope with one lens; observed tiny living organisms in pond water called "animalcules"

"animalcules"

tiny living organisms in pond water

Leeuwenhoek’s achievement

First to study magnified cells

MATTHIAS JACOB SCHLEIDEN

Botanist who focused his interests on the study of plant cells

THEODOR SCHWANN

Examined animal cells and found that all bodies of living organisms are made up of cells

RUDOLF CARL VIRCHOW

Proposed the third tenet in the cell theory, explaining where new cells originate

FIELD OF VIEW (FoV)

How much of the specimen we can be able to see through a microscope

FIELD OF VIEW (mm) FORMULA

Field number of eyepiece / Objective magnification

FIELD NUMBER (FN)

Diameter of the image area that is engraved on the eyepiece

PROKARYOTIC CELL

First kind of cell to develop (~3.5 billion years ago); simple organisms possessing cells that are smaller in size with simple internal structures; reproduce very fast; examples are bacteria, blue-green algae, and archaeans

PLASMA MEMBRANE (PROKARYOTIC)

Semipermeable membrane that allows waste products out while preventing essential products from leaving

CELL WALL (PROKARYOTIC)

Rigid wall that maintains cell shape, especially when exposed to water influx

CAPSULE

Protective layer made up of polysaccharides lying outside the cell wall

NUCLEOID REGION

Irregular-shaped region without a distinct nucleus where DNA is stored

CYTOPLASM (PROKARYOTIC)

Lacks distinct interior compartments, and organelles are spaced

RIBOSOME (PROKARYOTIC)

Small structure where proteins are made

PLASMID

Small, circular DNA molecule found mainly in bacteria that carries additional genetic information

FLAGELLUM (PROKARYOTIC)

Long, whip-like structure that helps a cell move (allows locomotion)

FIMBRIAE

Small, bristle-like fibers that help bacteria attach to surfaces

CONJUGATION PILI

Tubular structures that function for cell-to-cell communication (some bacteria develop drug resistance across generations)

EUKARYOTIC CELL

Evolved about 1.8 billion years ago; larger size and more complex structural components; genetic material (DNA) encased within a distinct nucleus; many membrane-bound interior compartments; examples are fungi, plants, animals, and protists

CELL/PLASMA MEMBRANE (EUKARYOTIC)

Thin barrier that separates the cell from the external environment and acts as a gatekeeper for regulating what enters and leaves

CELL WALL (EUKARYOTIC)

Rigid layer that gives protection, support, and shape to the cell and is made up of the polysaccharide cellulose

CYTOPLASM (EUKARYOTIC)

Jelly-like substance that fills the cell and holds the organelles in place

CYTOSOL

Fluid portion of the cytoplasm, mainly made of water and surrounding the organelles

NUCLEUS (EUKARYOTIC)

Storehouse of genetic information in the form of DNA and protects it from damage

DNA

Long chain of molecules divided into genes that contain instructions for making proteins

CHROMATIN

DNA packaged with histone proteins

NUCLEUS ENVELOPE

Encloses the DNA and contains holes called nuclear pores that allow large molecules to pass between the nucleus and cytoplasm

NUCLEAR PORES

Holes in the nuclear envelope allowing large molecules to pass between nucleus and cytoplasm

NUCLEOLUS

Dense region inside the nucleus where ribosomes are produced

RIBOSOME (EUKARYOTIC)

Small structures that make protein; enter through nuclear pores into cytoplasm where protein synthesis occurs

ENDOPLASMIC RETICULUM (ER)

Interconnected network of thin and folded membranes forming a maze of enclosed spaces in the cytoplasm

LUMEN

Interior of the ER maze where processes like protein and lipid production occur

ROUGH ER

Covered with ribosomes; makes proteins for membranes and secretion

SMOOTH ER

Lacks ribosomes; makes lipids and helps break down drugs and alcohol

GOLGI APPARATUS

Layered stack of membranes that modifies, sorts, and delivers proteins

VESICLES

Small membrane-bound sacs that transport proteins from the ER to the Golgi apparatus

VACUOLES

Membrane-bound sacs that store water, nutrients, wastes, and other substances

LYSOSOMES

Organelles containing digestive enzymes that break down wastes and worn-out cell parts

PEROXISOMES

Organelles surrounded by a single membrane, containing digestive enzymes like catalase for breaking down toxic materials

MITOCHONDRIA

Supply energy to the cell; round/oval shaped organelles with two membranes

PLASTIDS (CHLOROPLASTS)

Help plants convert solar energy into chemical energy and are involved in photosynthesis

THYLAKOIDS

Outer and inner membrane sacs inside chloroplasts containing chlorophyll

GRANUM

A stack of thylakoids

STROMA

Liquid portion of chloroplasts

CENTROSOME

Small, dense region of cytoplasm and serves as the main microtubule organizing center (MTOC)

CENTRIOLES

Cylinder-shaped organelles made of nine triplets of microtubules arranged in a ring