UNIT 3 REVIEW

Theory

All living things are made of cells, Theory or law?

Theory

Species evolve over time through natural selection, Theory or law?

Law

Objects fall to the ground due to gravity at a predictable rate, Theory or law?

Law

Energy cannot be created or destroyed, only transformed, Theory or law?

Leeuwenhoek

Used a single-lens microscope to observe living cells (protists, bacterial) in which he called “animalcules”.

Cell theory

All living organisms are composed of one or more cells, Cells are the basic units of structure and organization or all living organisms, cells arise only from previously existing cells, with cells passing coping of their genetic material on their daughter cells.

Zacharias and Jassen

Credited with creating the first compound microscope

Hooke

Improved compound microscope; used it to view cork

Leeuwenhoek

Crafted powerful single-lens microscopes (up to 300x mag.) first to observe living cells.

Light microscope improvments.

Enhanced lenses and ilumination allowed for clearer cell observation

Hook

Observed and named “cells” in cork using a compound microscope

Schleiden

Proposed that all plants are made of cells

Schwann

proposed that all animals are made of cells; concluded all living cells are composed of cells.

Virchow

Stated that all cells come from pre-existing cells (“Omnis cellula e cellula”)

Magnification

abillity to enlarge an object

resolution

abillity to see objects clearly that are magnified

Mircoscopes increase:

resolution

Unaided eye

10m to 1 mm

Light microscope

1 ňm to 100 nm

Electron microscope

100 ňm to 0.1 nm

Compound light microscope

Allows light to pass through a specimen and uses to lenses to form an image.

observes ALIVE OR DEAD specimens or tissue

Total mag. -1000-2000x

2D

Dissecting Microscope

Best used to observe physical characterisntics of alive or dead specimen. USES LIGHT

Used for dissection

Magnification up to -50x

3D

Electron microscope

Uses a beam of electrons instead of light to magnify image.

Used to examine only NONLIVING CELLS AND TISSUE.

two types- Transmission and scanning.

Scanning Electron microscope

Produces 3D IMAGES of the specimens surface and produces an image 100,000 times its original size

Biological speciments: Cells, bacteria, pollen. USES LUBRICATION.

Resolution- 1-10 nm

Transmission Electron Microscope

Magnifies from 50x to over 500,000x

Used to examime:

1. internal structure of cells and tissues ex: organelles, membrane, virues

2. crystalline structures in materials science ex: atomic arrangments.

Transmits electrons through the sample, revealing internal details, sample must be ulta thin

PRODUCES 2D IMAGES

Transmission Electron Microscope

A student is studying the internal structure of a mitochondrion to better understand how energy is produced in cells. The organelle MUST BE SLICED EXTREMELY THIN and placed in a VACUM. What type of microscope would best allow the student to view these internal structures?

Dissecting microscope

A fields biologist wants to obsever the external body parts of a live beetle larva to study its development. The organism is too large to fit on a typical microscope slide and needs to stay alive during observation. What type of microscope would best allow the student to view these internal structures?

A middle school class is examining onion skin cells to learn about cell membranes and nuclei. They prepare a wet mount slide and observe the cells at 400x mag. Using visible light. What type of microscope would best allow the student to view these internal structures?

compound light microscope

A team of researchers wants to examine the surface of a pollen grain from a flowering plant to study its texture and outer structure and extremely hight mag. and resolution. The sample must be coated with a conductive material and cannot remain alive. What type of microscope would best allow the student to view these internal structures?

scanning electron microscope

Compound light microscope

A student wants to view live single celled pond organisms like Euglena and paramecuim to study their movement and cell structure usung stained and unstained slides What type of microscope would best allow the student to view these internal structures?

Dissecting microscope

A forensic botanist needs to examine the surface texture of small plant seeds collected from a crime scene. The seeds must be examined in 3D at low magnification while remaining undamaged and uncoated. What type of microscope would best allow the student to view these internal structures?

Transmission electron microscope

Cell biologists are researching the internal untrstructure of chloroplasts to understand the arrangment of thylakoid membranes. the specimen must be sliced very thin and viewed at extremely high resolution. What type of microscope would best allow the student to view these internal structures?

eukaryotic

Nucleus, vacuoles, ER., chloroplasts, golgi apparatus, mitochodria, lysosomes.

Both eukaryote and prokaryote

Cell wall, Cell membrane, DNA, cytoplasm, ribosome

cilla

slender projections built from protein filaments called in Cells | Characteristics, Structure & Function. They move fluid or substances across the cell.

flagella

Microscopic, whip-like appendage that protrudes from certain cells and microorganisms to provide movement. propels the cell.

pilli

hair-like protein appendages found on the surface of many bacteria and archaea that help cells attach to surfaces, share DNA, and move.

plasmid

a small, circular, double-stranded DNA molecule that exists and replicates independently of a cell's chromosomal DNA. found in nucleiod region

tenets

principles

plant cells

basic living units of green plants and other organisms in the plant kingdom

animal cells

a basic structural and functional unit of life in animals

cell membrane

a thin, flexible barrier that surrounds every living cell, separating its internal contents from the outside environment.

Highly selective barrier

a membrane that allows specific molecules or ions to pass through while actively blocking others

permeable

the ability of a cell membrane to let substances pass through it.

active transport

Requires ATP (energy). Moves materials from low to high concentration (AGAINST THE GRADIENT)

• Uses protein pumps or transport proteins

• . Examples: Sodium-potassium pump- moves ions in nerve cells.

Endocytosis: cells take in larger particles

Exocytosis: cells push out large waste or substances.

passive transport

Does not use ENERGY (ATP). Moves materials from high to low concentation (with the gradient)

• exampels are: osmosis and diffusion

cell wall

a tough, rigid outer layer that sits just outside the cell membrane to give cells structural support, shape, and protection, made of tough carbohydrates/cellulose.

cytoplasm

the thick, jelly-like fluid that fills the inside of a cell and surrounds its internal structures. made of protein

ribosome

microscopic cellular structures made of ribosomal RNA and proteins that build proteins by translating genetic instructions. Made of RNA.

Nucleus

a membrane-bound organelle that stores a eukaryotic cell's genetic material (DNA) and acts as the control center for cell activities. Prokayote do not have it.

Nuclear membrane (envelope)

a double-membrane barrier that surrounds the nucleus in eukaryotic cells, separating the genetic material from the cytoplasm

nucleolus

is the largest, dense, non-membrane-bound structure inside the nucleus. creates ribosomes. essential for protein synthesis.

Chromatin

a complex mixture of DNA and proteins that packages long DNA molecules into a compact, dense shape inside the cell nucleus

ER.

A continuous network of membrane-enclosed sacs and tubes found in the cytoplasm of eukaryotic cells that handles protein and lipid production. Made of a phospholipid membrane,

Microtubules

Hollow, tube-like structures made of protein subunits that give eukaryotic cells their shape and help transport materials inside them.

Microfilaments

the thinnest protein fibers of the cell cytoskeleton

golgi apparatus

a membrane-bound organelle in eukaryotic cells that modifies, sorts, and packages proteins and lipids for transport in vesicles.

Lysosomes

a membrane-bound cell organelle that contains digestive enzymes to break down waste, old cell parts, and foreign invaders.

hypotonic

an external environment that has a lower concentration of dissolved solutes (particles like salt or sugar) than the fluid inside a cell.

hypertonic

an external environment that has a higher concentration of solutes (like salt or sugar) compared to the inside of a cell

isotonic solutions

a fluid that has the same concentration of solutes (like salt or sugar) as another solution, such as the inside of a cell, separated by a cell membrane

osmosis

the passive movement of water molecules through a semipermeable membrane from an area of higher water concentration (lower solute concentration) to an area of lower water concentration (higher solute concentration)

Vesicles

transports and stores materials

Ocular lens x Fine adjustment

Multiply to determine the total magnification you have in a compound light microscope.

proteins

The cell membrane contains channels and pumps made of

Four types of eukaryotic cells

Plant, animal, protists, and fungal

Chloroplasts

• Site of photosynthesis

contains chlorophyll to capture sunlight

Large central vacuole

Maintains tugor pressure for structural support

Centrioles

help organize microtubules in cell division, part of centrosomes.

Plasma membrane

Another word for the cell membrane, found in all cells.

• made of a phospholipid bilayer (double layer of fat)

• Selectively permeable

. Maintains homeostasis.

Facilitated diffusion

uses proteins to help mover larger or charged particles

• examples is glucose or ions.

Mitochondria

Membrane bound organelle

• chemical energy production (ATP)

Rough endoplasmic recticulum

protein production, ribosomes are present

Smooth endoplasmic reticulum

Lipid (fat) production, ribosomes are not present

Cytoskeleton

network of filaments and fibers that provide structure to the cell