Bio 7 Flashcards
When was the cell discovered and by who?
in the 1600s (after the invention of the microscope), and by Robert Hooke
why were they named cells?
they looked like small chambers
With little know about cells, the cell theory was created, what was it?
- all living things are composed of cells
- cells are the basic unit
- new cells come from old cells
What are the different microscopes that can be used/ have been used to explore the cell?
light microscope
electron microscope
scanning tunnel microscope
scanning probe microscope
light microscope and compound light microscope
light passes through lenses to produce a magnified image
- compound light microscope: two lenses
Electron microscope
forms image of specimen using beam of ELECTRONS, placed in vacuum chamber
TWO TYPES:
- TEM (transmission electron microscope)
-SEM (scanning electron microscope)
TEM versus SEM
TEM: electron beam is aimed at a very small part of specimen coated in METAL IONS, reveals internal structure
SEM: coated in METAL and 3D image is formed
scanning tunneling microscope (STM)
can be used to study living creature, uses needle like probe to measure different things, this often means metal
What is the STM mainly used for?
looking at metal at an atomic level
What is the most common microscope?
The light microscope, it is the cheapest though still very expensive
Scanning Probe microscope
NEWEST, uses little probes that produce images by scanning surfaces, show REALLY SMALL things
Micrograph
Image made by microscope
Magnification
ability to make image appear larger (microscopes have magnification)
Resolution
Measure of clarity in an image (how clear is what I am seeing?)
Why do mitochondria and chloroplasts have a large surface area?
Because they are much more efficient. This also applies to most organelles in an organism.
Why do cells need to have a large surface area?
so that they are able to push out and take in substances quickly
Prokaryotes
A cell without a nucleus, can be a single celled organism like ameba
-they are small and adapt well
How did prokaryotes evolve into Eukaryotes? And what is this theory called?
(Endosymbiotic Theory)
Starts with two fused pros, then a photosynthetic pro fuses in.
Where is DNA found in Prokaryotes?
It is found as a single extremely long circular molecule in the cytoplasm, the region where it is is called the nucleoid
Eukaryotes
an organism whose cells have a nucleus
-plants animals fungi
Where is DNA found in Ekaryotes?
within the nucleus
Cilia versus Flagella
Cilia are hair like structures protruding from Eukaryotes, Flagella are thread like structures protruding from Prokaryotes.
Cytoskeleton
Framework of a cell
- many different microfilaments& microtubes
What is a Centriole? What could it be compared to?
There are generally two centrioles in a cell near the nucleus, they are made up of many microtubules
-Centrioles organize a cells division, for instance teachers help divide students into a class
microfilament versus microtube
filaments- flexible strands that help the cell to move
tubes- hollow tubes maintaining cell shape and transport things
- also form centrioles that organize the cells division
what are the three parts of a cytoskeleton?
microfilament, microtubes, and intermediate fibers
Cell membrane
outer (and sometimes inner) shell of the cell
-it determines what leaves/enters the cell
What is the make up of the cell membrane?
phospholipids- (phosphate group+two fatty acids) has a polar head& non polar tail
These create the lipid bilayers- (FOUNDATION), two phospholipids tail to tail
proteins are imbedded in these
What are the tiny different parts of a cell called?
organelles
Nucleus
At the center of a Eukaryote, it contains DNA and basically instructs the organelles
4 main parts of the nucleus
Nuclear Envelope
Nuclear Pores
Nucleolus
Chromatin
Nuclear Envelope
layer around nucleus separating it from the cytoplasm
Nuclear Pores
Holes in the Nuclear envelope where RNA flows out of
Nucleolus
Dense area in the center of the nucleus where ribosomes can be partially assembled
Chromatin
granular material in the nucleus mixed of DNA bound to Proteins
-in cell division these strands become even more tightly bound, they become chromosomes
When a cell divides what happens to the Chromatin
It condenses to form chromosones
Ribosomes
Structures on which proteins are made from RNA
Where are ribosomes found?
They are found commonly on Endoplasmic Reticulum, free floating ribosomes are called free ribosomes
Endoplasmic Reticulum (ER)
A system of membranes that when it has ribosomes on it will add components to the proteins being made
When it is smooth the ER will generally make lipid components
Rough versus Smooth ER
Rough ER means that it has Ribosomes and is used to transport the proteins made by ribosomes
Smooth ER has no ribosomes and instead assembles lipids/ breaks down toxic substances
Vesicle
Tiny organelle used to transport substances
Where are proteins sent to be packaged/distributed?
Golgi Apparatus
-flattened membrane sacs that can serve as packaging and transportation
Lysosomes
The cleaners of the cells containing enzymes, they remove reuse old organelles/molecules
Vacuoles
More large saclike structures that are considered the storage for the cells, they are found in plant cells and animals cells
Mitochondria
Organelles that harvest energy from food
Chloroplasts
Organelles that harvest energy from the sun (they have a green tint)
They use this energy to make carbohydrates from from carbon dioxide and water
-THESE ARE ONLY FOUND IN PLANT CELLS
What are the most common features of a cell?
- membrane
- cytoplasm
- Cytoskeleton
- Ribosome
- Genetic material
What is possibly the ancestor of mitochondria?
Prokaryotes
Cell Wall
structure surrounding the membrane that provides support, it is found in plant cells
Central Vacuole versus Vaculoes
One is bigger than the others
Cell Membrane versus Cell Wall
The Cell membrane is a less structured layer that regulates what enters/leaves the cell while the cell wall is porus but provides protection
What is the lipid bilayer and how does it work?
This is what the membrane is often made of, it has two layer of lipids and is hard for molecules to get through
The heads of the lipids are polar and face outward, and tails of the lipids are non polar (hydrophobic) and face inwards
what do Protein channels and carbohydrates in cell membrane do?
These are imbedded in the membrane, proteins pump material in and out and the carbs identify the materials
What is concentration and how do you find it?
Concentration is the amount of solute in a solvent
mass of solute/volume of solvent
Diffusion
the process of a solute spreading itself out in a solvent,
EX: if inside the cell there is a concentration of 1/10 and outside there is a concentration of 2/10 then the solute will try to move into the cell
Why does Diffusion happen
It happens just because of probability, the solute moves around in the solvent and naturally more will end up moving into a lower concentration then those coming out of the concentration because the lower concentration has so few molecules
Dynamic Equilibrium
When there is equal concentration between any two areas, happens AFTER diffusion or osmosis
Osmosis
A similar process to diffusion, it occurs when water molecules (often the solvent) spread themselves out to reach and equilibrium
What will happen when to much water enters the cell through osmosis
The cell may burst, however, when it is a plant cell, the vacuole storing the water is often strong enough to stay together.
Is a larger or smaller cell more effective
The smaller cell
isotonic
after a dynamic equilibrium in reached, when there is an equal concentration on either side of the membrane
hypertonic
the part of the solvent with less of the solute, ex: the cell was hypertonic so the water was sucked out of it through osmosis
hypotonic
the part of the solvent with less of the solute, it has a lower osmotic pressure. A cell that is hypotonic will grow as water rushes in
Facilitated diffusion
when protein channels only fit certain proteins or molecules
Some channel proteins act as pumps, one of the most important ones are ____
Sodium Potassium Pumps
What do sodium-Potassium pumps do?
They give the cell a negative charge by pumping out 3 molecules of sodium , and only pumping in 2 molecules of potassium
active transport
proteins that can move molecules often against the concentration gradient
endocytosis
Process of taking molecules into the cell, this includes a vesicle.
phagocytosis
Process of consuming certain molecules
pinocytosis
The process of creating small vaculoes to store certain molecules
exocytosis
The process of pushing certain molecules out of a cell, this uses a vesicle
When water can pass through something, it is ___
Permeable
What are the differences in organisms caused by?
Differences in the ways cells preform their tasks
Unicellular versus Multicellular
Having just one cell (that adapts and responds like other organisms), or having many cells that work together to adapt and respond.
Cell specialization
How cells begin to develop differently to preform different tasks
What are some examples of cell specialization?
red blood cells (transport oxygen)
cells in the pancreas (produce proteins)
guard cells (monitor plants oxygen levels)
How does cell specialization differ between plants and animals?
Animals need specialization for more biological processes, plants are more chemical
What are the biological levels of organization?
Cells, tissue, organs, and organ systems
Tissues
Clumps of similar cells doing the same processes but together.
Organs
Groups of DIFFERENT types of tissues to do complex processes
Organ systems
Groups of different organs, do more complex processes
What kinds of organisms have cell specialization?
multicellular
How are single celled organisms similar to multicellular organsims?
Single celled organisms adapt and respond to their environment in the same way
What happens during diffusion?
A solute moves through a solvent randomly and inevitably ends up spreading out evenly, resulting in a dynamic equilibrium
phagocytosis versus pinocytosis
Phagocytosis is the process of the cell engulfing/ repurposing old materials, pinocytosis is the process of creating small vacuoles for storing materials.
What is the difference between and active transport and diffusion?
Active transport requires ENERGY, and is moving AGAINST concentration difference. Diffusion is a process that just happens naturally.
in what type of organisms are chloroplasts found?
Plants
What are the universal cell structures?
(there are 5)
- cell membrane (around the cell)
- cytoplasm (general interior of cell)
- cytoskeleton (structure/support of cell)
- ribosomes (builds proteins, workers)
- Genetic material (nucleus or nucleotide)
nucleoid versus nucleus
nucleus is separated by nuclear envelope, nucleoid is in a cell without nucleus(prokaryotic), it is just a clump of genetic material.
primary versus secondary cell wall
The primary cell wall is the first formed wall, over time it becomes the secondary cell wall.
what happens as the cell wall becomes secondary
it becomes rigid and thick
What are the main differences between an animal and plant cell.
The cell wall, the vacuoles, the centrioles, and the chloroplast.
Why do plant cells often have one large vacuole?
As plant cell mature the vacuoles grow and fuse into just one.
these are often filled with water
What are the parts of a vacuole?
The insides: often chemicals or water
Crystals: solid substances give flowers pigment
Tonoplast: around the vacuole
What do chloroplasts do?
Chloroplasts, which are only found in plant cells, cause the plant to be green and help with the process of photosynthesis
Luecoplast versus chromoplasts
Luecoplasts store proteins, starches and lipids while chromoplasts produce and store pigments that impact color
chloroplast versus chromoplast
Chromoplasts, like Luecoplasts, store things, Chloroplasts are similar to mitochondria and convert light energy into chemical energy
where were ribosomes assembled?
nucleolus
What are the common purposes of protein channels?
pass messages, transport enzymes, transport proteins
how are vesicles formed?
they are formed with cell membranes
Are plant or animal cells cooler?
plant cells
Why is the central vacuole of a plant cell so important?
It is what causes plants to grow, and it is almost impossible to pop because of the tonoplast that surrounds it.
passive versus active transport
a passive transport requires no energy, active needs energy
What is the concentration gradiant?
The difference in concentration throughout a solvent, often forms a gradient
Should you say equilibrium or dynamic equilibrium?
DYNAMIC EQUILIBRIUM
If a cell is placed in water and there is a stronger concentration of salt inside that cell, AND the membrane is only preamble to water, what will happen.
Water will mover towards the high concentration, this is hypotonic.
Why do active transports increase the concentration gradient?
by increasing the concentration gradient they store and invest energy, when the cell needs energy, the protein channel will open up and energy will be gathered by the sudden flow of the solute.
Receptor Protein
A protein that binds to a specific signal molecule enabling the cell to respond to the signal
What are the functions of a receptor protein
- cause changes in permeability of cell membrane
- trigger messengers formation within cell
- Activate enzymes
Ion Channel
a protein channel made specifically for an ion
Carrier Protein
A form of active transport that carries a substance across a membrane
Proton Pump
Similar to the Sodium/potassium pump, the proton pump moves protons across the cell membrane (it is a form of active transport)
-This uses H+ ions
What is an epithelial tissue?
What are the different types and how can they be arranged?
Epithelial tissues can be
-squamous- short and squished
-cuboidal- cube shaped
-columnar- taller
-can be arranged simple, stratified, or psuedostratified
What is muscle tissue?
Skeletal- moves skeleton
smooth- internal movement
cardiac- heart
Connective tissue
There are many types:
- loose (under skin)
- Adipose (blood)
- Cartilage
- Bone
- Fibrous- ligament
Nueral Tissue
It is irritable (receives stimuli) and conductive (passes on stimuli)
Who created the parts cell theory
hooke- basic unit of life
Schledien- animals are made of cells
Schwan- plants are made of cells
virchow- old cells come from new cells
