Biology unit 4-cells

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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.

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