Unit 3 Bio - Microscopes and Cell Membrane

Robert Hooke

invented the word “cells” by looking at a piece of cork under a microscope; the little holes looked like chamber cells

Anton Leeuwenhoek

examined pond water and human mouth cells; discovered “bacteria”

Matthais Schleiden

all plants are made of cells

Theodor Schwann

all animals are made of cells

Rudolph Virchow

new cells are produced from the division of existing cells

all living things are made up of cells cells are the basic units of structure in living things new cells are produced from existing cells

What are the 3 parts of cell theory?

Stage

where the glass slide is placed for observation

objective lens

magnifies the image of the specimen

stage clip

the clips that hold the glass slide on the stage

light source

transmits light through the specimen for better viewing

eyepiece or ocular lens

at top of microscope; magnifies the real image/specimen

diaphragm

controls the angle of the light

coarse adjustment

allows for quick focusing on the specimen by moving the stage up and down

fine adjustment

focuses the image when viewing at higher magnification

arm

supports the tube and connects the base

body tube

separates the objective and the eyepiece

light

Light Microscope or Electron Microscope? uses light to create images of outlines like cells and organisms

light

Light Microscope or Electron Microscope? used on living and non-living specimens

light

Light Microscope or Electron Microscope? Magnification : low (x4), medium (x10), high (x40)

electron

Light Microscope or Electron Microscope? uses a beam of electrons to create images

electron

Light Microscope or Electron Microscope? sees cells as small as 1 millionth of a meter,

electron

Light Microscope or Electron Microscope? vacuum seal organisms/cells so they are non-living

TEM

Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM)? explores cell structures/large molecules

TEM

Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM)? 2D images

TEM

Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM)? specimen must be sliced ultra thin before being examined

SEM

Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM)? scans the surface of an organism's/specimens

SEM

Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM)? 3D

SEM

Transmission Electron Microscope (TEM) or Scanning Electron Microscope (SEM)? x26 magnification

Stains

dyes used on specimens so they can be seen clearly under microscope

Ribosomes

structures found inside cells that is involved making proteins

Cell membrane

boundary of the cell, controls what goes in and out

Cytoplasm

gel like fluid that fills the cell and gives it its structure

DNA

genetic material/information that makes up the function/structure of an organism

ribosomes, cell membrane, cytoplasm, and DNA

What organelles do prokaryotes and eukaryotes share?

Prokaryotes

have no nucleus, no membrane bound organelles (freely moving), contain bacteria and archaea cells (unicellular)

Eukaryotes

have a nucleus, membrane-bound organelles, contain animal, plant, fungi, and protists cells (unicellular and multicellular)

Archaea

prokaryotes that live in harsh and extreme environments

bacteria

prokaryotes that can destroy reproduction, the cell wall, and proteins

Cell Wall

structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid (protists/bacteria/archaea/plant)

Flagella

hairlike structure that acts primarily as an organelle of motion in the cells of many living organisms (bacteria/archaea)

Golgi apparatus

transport and modifies proteins and lipids into vesicles for targeted destinations (animal)

Mitochondria

all cells and chloroplast in plant cells function and energy processing

lysosomes

a membrane-bound cell organelle that contains digestive enzymes (animal)

Fluid Mosaic Model

describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character

Integral proteins

helps transport certain material across the cell membrane

Peripheral proteins

a class of membrane proteins that attach to the lipid bilayer; support, communication, enzymes, and molecule transfer in the cell.

Cholesterol

helps maintain flexibility of membrane

Phospholipids

makes up the bilayer; phosphate heads are polar, hydrophilic; two lipid tails are hydrophobic and nonpolar

Glycolipids

involved in cell to cell recognition; maintain stability

Glycoproteins

enable cell to cell recognition

Active Transport

most chemicals use it, requires energy (ATP) - cellular energy; low to high concentration; uses carrier proteins and ATP to transport materials against concentration gradient

exocytosis

AT; materials get transported outside of a cell caused by a vesicle

endocytosis

AT; how materials get inside the cell

phagocytosis

endocytosis; engulf harmful bacteria, membrane forms vesicle around the bacteria and then the enzymes destroy it

pinocytosis

endocytosis; surrounds things that have already been dissolved

receptor-mediated endocytosis

uses receptors to import macromolecules from the extracellular fluid. Occurs in very small concentrations

Passive Transport

does not require energy; high to low concentration gradient (moved with it)

Diffusion

when molecules get crowded and they would find spaces that aren’t crowded.

Osmosis

diffusion; movement of water molecules

Facilitated diffusion

particles use a channel protein to cross the membrane: large, ionic, and polar molecules

Simple diffusion

particles move directly through the cell membrane: small and non-polar

Concentration Gradient

occurs when the concentration of particles is higher in one area than another

Protein Channels

PT; span the membrane and make hydrophilic tunnels across it, allowing their target molecules to pass through by diffusion

Protein Pumps

AT; move ions against the gradient of concentration across membranes

Small hydrophobic molecules and gasses like oxygen and carbon dioxide

What molecules/particles can easily go through the membrane?

Large molecules, polar molecules, and ions, glucose, amino acids, proteins, they need a channel or pump

What molecules/particles have a harder Time Moving Through the membrane?

polar molecules like water have a harder time because the inside of the cell membrane is a lipid which is nonpolar. This means they are hydrophobic and hate the water that is going through them. They want to try and get away from it

Why do polar molecules like water, have a harder time going through the membrane?