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50 terms

Biology unit 4-cells

STUDY
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list the three main parts of the cell theory
1) all living things are composed of cells
2)cells are the basic units of structure and function in living things
3)New cells are produced from existing cells
Prokaryotic cells
do not contain nuclei
have genetic material that is NOT in nucleas
carry out activity associated with living things
grow, reproduce, respond to the env. contain cell wall and membrane, DNA in middle, ribosomes and flagellum
few internal stuctures-SMALL AND SIMPLE
Eukaryotic Cells
contain nuclei
dozens of internal structures and membranes
DNA in nucleas
can live as single-celled or multicellular organism
LARGE AND COMPLEX
example of Prokaryote
bacteria
example of eukaryote
plants, animals, fungi
endosymbiotic theory
some structures in the modern eukaryotic cells developed from early prokaryotes, such as mitochondria and in plants, chloroplasts.
similarities and differences between plant and animal cells
different-plants have vacuole, chloroplasts, and cell wall. more square. animal cells have centrioles and are rounded. other than that, share many structures
cell wall
only in plant cell around the outside. provides support and protection for the cell. supports from the cell exploding when it takes in too much fresh water.
plasma membrane
Regulates what enters and leaves the cell and also provides protection. BOUNDARY between the cell and it surrounding environment (key structure regulating between the cell and world)
vacuole
in plant and animal, but known for the plant cell. large-stores materials such as water, salts, proteins and carbs. supports heavy structures when vacuole is full making it rigid to over come gravity
nucleus
controls nearly all the cells DNA and with it, the coded instructions for making proteins and other important molecules. located in the cell in the nuclear envelope
nucleolus
where the assembly of robiosomes begins. looks like a circle within the nucleus
chloroplast
organelles that capture light energy from the sun and convert it to chemical energy in a process called photosynthesis
mitochondria
are organelles that convert the chemical energy stored in food into compounds that are more convenient. think cellular respiration. have waves in picture
golgi apparatus
modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage inside the cell and secretion outside the cell
endoplasmic reticulum smooth
site where lipid components of the cell membrane are assembled. also complete tasks such as detoxifying.
endoplasmic reticulum rough
synthesis of proteins on the surface-ribosomes assemble the proteins.
ribosome
make proteins. they are small particles of RNA and protein found throughout the cell
analogy of a cell membrane
the cell membrane is like the walls of your house, protecting from the outside world.
function of plasma membrane
allows nutrients into the cell as needed and also allows waste and other projects to leave the cell. is responsible for maintaining HOMEOSTASIS- in the cell of what we do and don't need.
explain the structure of a plasma membrane
a phospolipid bilayer. it has a tail which is in the inner membrane and is hydrophobic-afraid of water, and the heads are on the outside and are hydrophilic-can come into contact with water.
passive transport
movement that does not require energy. particles move from an area of high concentration to an area of low concentration. and particles move with the concentration gradient.
concentration gradient
the difference of a substance across space. ex-person opens a bottle of perfume and sprays it. concentration is high from that person's body. then it diffuses and moves across air. the difference of concentration from the body across air is this.
what are the 3 types of passive transport?
simple diffusion, facilitated diffusion, and osmosis
simple diffusion
the random movement of molecules from an area of high concentration to an area of low concentration. when everything is the same concentration it is a dynamic equilibrium
dynamic equilibrium
when everything has the same concentration. molecules are still moving, but at an equal rate.
facilitated diffusion
sometimes this passive transport of molecules across the membrane requires the aid of transport molecules. the molecules don't go thru the membrane, but thru the transport proteins
osmosis
the diffusion of water across semipermeable membrane. water ALWAYS tries to reach an equal concentration on both sides of the membrane. HOMEOSTASIS
Hypotonic solution
lower concentration of water on the inside than outside. water will flow into the cell to maintain homeostasis. in an animal cell-the cell will burst-cytolysis. plant cell-will not burst because of cell wall.
what happens to a plant cell in a hypotonic solution (when they take in water)?
the turgor pressure increases, creating a rigid structure so the plant does not wilt. turgor pressure makes plant cells push against each other making the plant stand upright. like a balloon filled with air. if you push it, it will bounce back into place.
isotonic solution
equal concentrations of water inside as outside. water will flow into and out of the cell at equal rates to maintain homeostasis.
hypertonic solution
higher concentration of water inside the cell than outside. water will flow out of the cell to maintain homeostasis. animal cells-cell will shrink since all water is leaving the cell. plant cells-the cell membrane will pull away from the cell wall causing loss of turgor pressure and the plant will wilt.
plasmolysis
a plant losing water
cytolysis
a cell gaining so much water that an animal cell will burst and a plant cell will be fine because of cell wall and increase turgor pressure!
active transport
the pumping of molecules against their concentration gradient WITH the expenditure of energy (ATP)
what does against the concentration gradient mean?
it means that molecules use ATP to travel from low concentration to high concentration rather than the opposite.
endocytosis
the import of materials to the cell by the infoldings of the plasma membrane.
name three types of endocytosis
phagocytosis-cell eating
pinocytosis-cell drinking
receptor-mediated endocytosis
phagocytosis
there is food present outside of the cells. the the cell pseudopods (extenuation of membrane) grab and eat food. then the vesicle swallows the food.
pinocytosis
fluid present outside the membrane. no pseudopods suck it in, but the vesicle just swallows fluid.
exocytosis
exact opposite of endocytosis. the export of the cell's materials by unfolding of the plasma membrane. exo sounds like exit, endo sounds like entrance.
what will you see under a microscope when a plant undergoes plasmolysis
The cell wall will still be in the same clearly defined rectangular shape. The membrane however, will have been sucked in by the vacuole taking everything with it. and all of the water that was pushing out, now is gone causing the plant to lose turgor pressure.
Adipose (lipid cells)
big large circular/rounded cells. empty looking-used for storage
nerve cell
more linear than round, flat, connected. used for communication/transportation of messages.
skin cells
layered, stacked, tightly packed. used for protection
blood cells
tiny cells, large amounts, small dots. flow to different parts of the body because they are so small they can fit into narrow spaces.
muscle cells
tightly packed, linear, organized, flexible. used for movement.
bone cells
Most compact/dense. little circular pattern. used for stability and protection.
why are cells so small?
if the rates of diffusion are the same, and you have a greater surface area to volume ratio, the molecules can get to most of the cell quicker if its smaller
Why are smaller cells better based off of surface area and volume ratio?
The bigger the cell gets, the larger the surface area, and you lose units of volume per surface area. The nutrients will not be able to get to all of the organelles as fast or intime for survival without having a bigger surface area to small volume ratio.