Microscopes and Cell Biology Lecture Notes

Vocabulary practice flashcards covering cell discoveries, microscope mechanics, cell theory, organelles, cellular transport, and plant physiology.

Robert Hooke

Scientist who in $1665$ used a rudimentary $30\times$ microscope to observe cork and coined the term “cells”.

Anton van Leeuwenhoek

Scientist who in $1674$ observed the first single celled microorganisms using a $500\times$ microscope.

Ocular lens

The lens of a compound microscope that a person looks into, also known as the eyepiece.

Objective lens

The lens in a compound microscope located closer to the specimen being viewed.

Field of view

The actual, unmagnified diameter of the area visible when looking through the eyepiece of a microscope.

Abiogenesis

The hypothesis, also known as spontaneous generation, that life can arise from non-living material.

Biogenesis

The theory, proposed by Virchow in $1858$, stating that living organisms can only arise from other living organisms.

Louis Pasteur

Scientist who studied fermentation and showed that spoiling could be slowed by killing microbes with heat and preventing their entry.

Cell Theory

The theory stating that all organisms are composed of one or more cells, the cell is the smallest functional unit of life, and all cells are produced from other cells.

Organelles

The specialized parts of a cell that perform essential functions.

Lysosomes

Small vacuoles or vesicles containing digestive fluids used by the cell.

Mitochondria

Structures responsible for cellular respiration, transforming food into other forms of energy.

Chloroplasts

Plant organelles containing chlorophyll that perform photosynthesis.

Centrioles

Organelles found in animal cells used in cell division to ensure daughter cells receive accurate copies of genetic material.

Phospholipid bilayer

Structure formed when phospholipid molecules line up with hydrophilic heads facing water and hydrophobic tails facing inward.

Fluid-mosaic model

A description of the cell membrane where molecules like proteins and carbohydrates are not fixed but move around like a fluid.

Brownian motion

The random motion of molecules occurring in liquids and gases.

Passive transport

Movement across a membrane that does not require the cell to expend energy, such as simple diffusion or osmosis.

Facilitated diffusion

Passive transport of larger molecules or ions through a membrane with the help of transport proteins.

Plasmolysis

The shrinking of a cell due to osmosis when placed in a hypertonic environment.

Turgor pressure

The outward pressure exerted on a cell wall due to osmosis when a cell is in a hypotonic environment.

Active transport

Movement of materials through a membrane requiring energy, often moving substances against the concentration gradient.

Phagocytosis

A type of endocytosis where the cell takes in solid material.

Pinocytosis

A type of endocytosis where the cell takes in liquid material.

Autotrophic

Organisms that can meet their own energy needs using photosynthesis.

Heterotrophic

Organisms that must obtain energy by consuming other organisms.

Waxy cuticle

A non-living coating produced by epidermal cells on a leaf to prevent excess water loss.

Palisade tissue cells

Tightly packed cells below the upper epidermis that serve as the primary site of photosynthesis.

Stomata

Small openings in the lower epidermis of a leaf that allow $\text{CO}_2$ in and $\text{O}_2$ out.

Xylem

Vascular tissue made of dead cell walls that forms tubes to transport water and minerals from roots to leaves.

Phloem

Living vascular cells that transport sugary sap produced by photosynthesis from the leaves to other parts of the plant.

Lenticels

Small white spots or openings on the bark of woody plants that allow for gas exchange.

Transpiration

The evaporation of water from the leaves of a plant.

Tropism

A plant's growth response to a stimulus, such as light ($\text{phototropism}$) or gravity ($\text{gravitropism}$).

Auxin

A hormone in plant stems that stimulates growth and concentrates on the darker side of a stem to cause bending toward light.

Cohesion

The tendency of molecules of the same type, such as water, to stick to each other.

Adhesion

The tendency of molecules to stick to different types of molecules, such as water sticking to cellulos e in xylem tubes.