Cells Flashcards
smaller units combined to make larger units
Hierarchy
Life originating from non-living material
ex. garbage –> rats
rotting food –> flies
mud –> frogs
Spontaneous Generation
Abiogenesis
life originating from life
Biogenesis
- microscope
- sends light thru object
- image is inverted
Compound Light Microscope
- microscope
- bounces light off object
- object has same orientation as on stage
Dissecting Scope
- microscope
- electrons are passed thru thin sections of object
- higher magnification due to resolution
- non-living material only
Transmission Electron Microscope
- microscope
- electrons are bounced off the object’s surface
- non-living material only
Scanning Electron Microscope
- year
* cell theory created by Schleiden + Schwann
1838
- year
* cell theory created by Virchow
1858
- year
* Pasteur disproves spontaneous generation; proves biogenesis
1865
Scientist:
Hooke
- discovered and coined the term “cells”
* developed 1st microscope
Scientist:
van Leeuwenhoek
1st to observe and describe micro organisms which he referred to as “animalcules”
Scientist:
Aristotle
one of the first scientists to believe spontaneous generation did NOT occur in higher level organisms
Scientist:
Redi
disproved spontaneous generation (by observing maggot development in opened and closed meat containers) but was DENIED by scientific community
Scientist:
Needham
thought to have proved existence of spontaneous generation but used erroneous method (with errors)
Scientist:
Spallanzani
redid Needham’s experiment correctly to disprove spontaneous generation
Scientists:
Schleiden + Schwann
created cell theory that states all life is composed of cells
Scientist:
Virchow
created cell theory that states all cells come from pre-existing cells
Scientist:
Pasteur
- credited with disproving spontaneous generation
* created flask that gathered microbes in neck
Scientist:
Margulis
created endosymbiont hypothesis
Scientists:
Uzzell + Spolsky
created membrane invagination hypothesis
Compare + Contrast:
Prokaryotic vs. Eukaryotic
BOTH –> types of cells
PRO –> does NOT contain a membrane bound nucleus
-Kingdom Monera
EUK –> contains a membrane-bound nucleus
-Kingdom Protista, Fungi, Plantae, Animalia
Compare + Contrast:
Endosymbiont vs. Membrane Invagination Hypothesis
BOTH –> refer to the origin of the eukaryotic cell
ENDO –> accepted; larger cell engulfed a smaller, simpler cell which became the membrane-bound nucleus
MEMB –> rejected; membrane folded in on itself and produced membrane-bound organelles
Major Cell Structures + Functions
4
- Cell Wall - found in plants, algae, and prokaryotes only
- Cell (plasma) Membrane - found in all cells, outer boundary of cell that separates internal processes from environment, contains receptors for external molecules that alter cell’s function
- Cytoplasm - found in all cells, portion of cell outside of nucleus, contains organelles
- Nucleus - found in eukaryotes only, control center of cell, contains genetic material (DNA)
Cell Structures:
Protoplasm
- colorless substance that is the living part of cells
* contains cytoplasm and nucleus
Fluid Mosaic Model
According to this model, a membrane is…
- a double layer of proteins and phospholipids
- fluid (rather than solid)
Scientists:
Singer + Nicolson
developed the Fluid Mosaic Model
Transmembrane Proteins
- permanently attached to membrane
- span entirety of membrane
- function as gateways to permit transport of specific substances across membrane
Peripheral Proteins
*membrane proteins temporaily attached to the outer membrane surface
Phospholipid Bilayer
two layers of phospholipid molecules
“water attracting”
*heads
Hydrophilic
“water dreading” - repell water
*tail
Hydrophobic
“little organs”
*smaller structures inside the cell that perform specific functions
Organelles
Organelles Structure + Function:
Mitochondria
Structure -
- double membrane
- cristae - increases surface area
- matrix - contains ribosomes + DNA
Function - converts energy to usable form
Organelles Structure + Function:
Ribosomes
Structure - free moving or attached to ER
Function - site of protein synthesis
Organelles Structure + Function:
Endoplasmic Reticulum (ER)
(Smooth + Rough)
Structure - extensive system extending thru cytoplasm from membrane to nuclear envelope
Function - storage + internal transport
- Smooth –> makes lipids
- Rough –> site for attachment of ribosomes
Organelles Structure + Function:
Golgi Apparatus
(Golgi Complex)
Structure - stacks of dislike membranes
Function - sorts and packages synthesized products
Organelles Structure + Function:
Lysosome
Structure - membrane-bound sphere
Function - site of digestion
Organelles Structure + Function:
Cytoskeleton
Structure - interconnecting microtubules + microfilaments
Function - assists in cell movement, provides support
Structures of the Cytoskeleton
5
- microfilaments (actin filaments) - give shape to the cell and support all of its organelles
- intermediate filaments - group of protein fibers that help maintain cell shape + spatial organization of organelles
- microtubules - assist in movement of organelles + DNA in cell division
- centrioles - involved with chromosome movement during cell division
- cilia + flagella - elongated appendages used to propel the cell
Compare + Contrast:
Chromatin vs. Chromosomes
BOTH –> genetic material
CHROMATIN –> uncoiled mass of chromosomes
CHROMOSOMES –> tightly coiled segments of DNA
Structures of the Nucleus:
2
- Nucleolus - does not have a membrane, present in non-dividing cells
- Nuclear Envelope - membrane that separates nucleus from cytoplasm
* pores - allow material to enter/leave nucleus
Compare + Contrast:
Passive Processes vs. Active Processes
BOTH –> types of transportation into/out of cell
PASSIVE:
- require no energy input
- movement from high to low concentration
- types: a. simple diffusion
b. facilitated diffusion
c. osmosis
d. filtration
ACTIVE:
- requires energy (ATP)
- movement from low to high concentration
- types: a. active transport
b. transport involving vacoles
Types of Passive Processes
4
- simple diffusion - movement of molecules from high to low concentration until equilibrium is achieved
- facilitated diffusion - transport proteins in membrane bind with molecules to help them pass across membrane
- osmosis - water molecules diffuse across membrane from high to low concentration
- filtration - movement due to a pressure gradient
Isotonic,
hypertonic,
hypotonic solutions
ISO –> at equilibrium, no net change in water movement
HYPER –> solution has higher solute conc. than cell, water leaves cell
HYPO –> cell has higher solute conc. than cell, water enters cell
water leaves the cell causing the cell to shrink/shrivel
Crenation
water enters the cell, causing the cell to burst
Lysis
Types of Active Processes
2
- active transport - proteins in membrane bind with molecules to cross membrane against concentration gradient (L–>H), requires energy
- transport involving vacuoles - bulk movement of large molecules into/out of the cell that can not be transported thru the membrane
- endocytosis (phago-, pino-)
- exocytosis
Sodium Potassium Pump
- example of active transport
* helps maintain high conc. of potassium ions + low conc. of sodium ions inside nerve cells
Compare + Contrast:
Endocytosis vs. Exocytosis
BOTH –> bulk movement of large molecules across the cell membrane
ENDO –> membrane envelopes molecules and moves them into cell
EXO –> vesicles fuse with membrane to move/release molecules out of cell
Compare + Contrast
Phagocytosis vs. Pinocytosis
BOTH –> movement of molecules into the cell
PHAGO –> “cellular eating”; intake of solid material into cell
PINO –> “cellular drinking”; intake of small droplets of fluid into cell
Compare + Contrast:
Cilia vs. Flagella
BOTH –> elongated appendages used to propel the cell
CILIA –> short, many (hundreds) per cell
FLAGELLA –> longer, fewer (1-8) per cell
Compare + Contrast:
Actin Filaments vs. Microtubules
BOTH –> structures of cytoskeleton
AF –> give shape to cell and support organelles
MT’s –> assist in movement of organelles and DNA during cell division
Compare + Contrast:
Transmission Electron vs. Scanning Electron Microscope
BOTH –> types of microscopes used to observe non-living material
TEM –> electrons are passed thru thin sections of object
SEM –> electrons are bounced off object’s surface
Compare + Contrast:
Rough ER vs. Smooth ER
BOTH –> both part of ER which functions as storage and internal transport
ROUGH –> site for attachment of ribosomes
SMOOTH –> makes lipids
Compare + Contrast:
Nucleus vs. Nucleolus
BOTH –> contain genetic material
NUCLEUS –> has a membrane
NUCLEOLUS –> lacks a membrane
