Biology Lab Midterm

Hypotheses

Tentative explanations to account for observations

Independent variable (IV)

The condition, factor, or input that an experimenter manipulates to observe its effect on an outcome

Dependent variable

The outcome being measured in an experiment

Control

Any factor that is intentionally held constant throughout an experiment

Replication

The process of repeating an experiment to verify its findings

Null hypothesis ($H^0$ )

A statement that assumes there is no relationship, effect, or difference between variables in an experiment

Alternative Hypothesis

A statement that suggests there is a difference, relationship, or effect in an experiment

Qualitative data

Non-numerical information that describes qualities, characteristics, and meanings

Quantitative data

Any information that can be counted, measured, and expressed in numerical values

Cell theory

• all living things are composed of cells

• cells are the basic unit of life

• all cells arise from pre-existing cells

Resolving power

The capacity of an optical instrument (such as a microscope or telescope) to distinguish two closely spaced points or objects as separate entities

The human eye has the ability to distinguish between objects that are about…

100 micrometers (0.1 mm) apart

Resolution

Sharpness of an image

Ocular lens

In the eyepiece, magnification of 10x

Revolving nosepiece

Holds the objective lens

Objective lens

Screwed into the nosepiece, 4x(scanning), 10x, 40x

Stage

Platform onto which slides to be viewed are placed

Condenser knob

Adjusts the amount of light that goes through the condenser lens

Condenser lens

Concentrates light before it reaches the specimen

Iris diaphagram

Regulates the amount of light before it reaches a specimen

Base

Bottom of the microscope

Arm

Back of the microscope, should be carried by this part

Main switch

Turns the microscope on and off

Light intensity knob

Adjusts the amount of illumination

Y-axis stage knob

Moves stage forward and backward

X-axis stage knob

Moves stage left and right

Coarse adjustment knob

Moves the stage up and down, should only be used with lower power lenses (4x and 10x)

Fine adjustment knob

Precisely regulates focus, should only be used with high power lens (40x)

Depth of field (DOV)

Thickness of the specimen

Field of vision (FOV)

Ruler (mm.) in the right eyepiece, used to measure specimen

All cells have…

• Plasma membrane

• DNA

• Metabolism (can perform chemical reactions with the help of enzymes)

Prokaryotes

Does not contain a membrane-bound nucleus (bacteria and archaea)

Eukaryotes

Contain a membrane-bound nucleus (protists, fungi, and animals)

Nucleus

Contains the DNA of the cell

Organelles

Mitochondria, rough endoplasmic reticulum (rough ER), smooth endoplasmic reticulum (smooth ER), golgi apparatus

Ribosomes

Contains RNA and proteins, site of protein synthesis

Extracellular matrix

Consists of proteins and carbohydrates, outside cell membrane

Histology

Study of tissues

Epithelial tissue

Sheet-like arrangement of tightly connected cells, converts organs and linings of organs, (simple squamous, simple cuboidal, simple columnar, stratified squamous)

Muscle tissue

Involved in contraction, striated and striped, (smooth, skeletal, cardiac)

Connective tissue

Provides protection and support for the body, most abundant tissue type, (adipose, blood)

Adipose

Fat tissue

Blood Cells

Suspended in liquid plasma, cells appear as individuals under microscope, (red and white)

Brownian motion

Movement of molecules

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration

Concentration gradient

A difference in the concentration of a substance between areas

Equilibrium

The concentration of a substance is the same in two areas

Osmosis

The movement of water across a selectively permeable membrane, type of diffusion

Solute

Molecules dissolved

Solvent

Used to dissolve solute

Solution

Combined results of solvent and solute

HYPeRTONIC

Solution outside of the cell contains a greater concentration of dissolved molecules than the inside of the cell

hypOtonic

Solution outside of the cell contains a lower concentration of dissolved molecules than the inside of the cell

Isotonic

The inside and outside of the cell have equal concentrations of dissolved molecules

Impermeable membrane

Solute cannot move across the membrane, osmosis occurs

Permeable membrane

Solute will diffuse from the inside to the outside until the two are isotonic