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Cell Review

cell review
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cell
basic unit of all living things
cell theory
1) all living things are made of cells
2) cells are the basic structural unit of all living things
3) all cells come from preexisting cells
importance of the discovery of the microscope
allowed scientists to better examine and classify cells as well as their organelles
Robert Hooke
first observed little blocks in a sample of cork through a primitive microscope, he came up with the name "cells"
cell membrane
surrounds the outside of a cell, controls what enters/exits the cell, found in both plant and animal cells
endocytosis
the process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell
exocytosis
the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out
hypotonic solution
in cells, solution in which the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell; causes a cell to swell and possibly burst as water enters the cell
homeostasis
tendency of a system or organism to maintain relative stability or internal equilibrium
levels of organization
cell; tissue; organ; organ system
prokaryotic cells
unicellular organisms that contain a cell wall, cell membrane, and similar organelles to eukaryotic cells, but they lack a nucleus, instead having a "nuclear region". they also have pili or flagella create movement
eukaryotic cells
unlike plant cells and prokaryotes, they lack a cell wall. these cells have membrane-bound organelles as well as a membrane-bound nucleus that contains the cell's DNA. they are generally part of a multicellular organism.
exceptions to the cell theory
viruses, mitochondria, the first cell
unicellular organisms
single-celled organisms able to carry out life processes by reproducing, growing, responding to their environment, or transforming energy
centriole
found only in animal cells, assists cell reproduction
endoplasmic reticulum
synthesizes proteins and prepares them for transport, forms parts of the cell membrane
golgi apparatus
final packaging center for proteins, exports materials throughout the cell
cytoskeleton
helps maintain cell structure
cell wall
found only in plant cells, helps maintain structure, made of cellulose
nucleolus
the organelle where ribosomes are made, synthesized and partially assembled, located in the nucleus
nucleus
contains the RNA and DNA
chromatin/nucleic acid
building blocks of DNA
amino acids
make up proteins
ribosomes
found throughout the cell and on the ER, create proteins
lysosome
contains digestive enzymes to aid in waste removal
hypertonic solution
in cells, solution in which the concentration of dissolved substances outside the cell is higher than the concentration inside the cell; causes a cell to shrink as water leaves the cell
isotonic solution
in cells, solution in which the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside a cell
osmosis
the diffusion of water across a selectively permeable membrane, a type of passive transport
diffusion
the movement of particles from high concentration to low concentration, a type of passive transport
active transport
requires the cell to use energy, small molecules are transported using proteins, larger molecules are transported through endocytosis or exocytosis
facilitated diffusion
the movement of molecules through the membrane with the help of a protein, a type of passive transport
plant cells vs animal cells
- have a cell wall and cell membrane, large water vacuoles, chloroplasts create energy through photosynthesis
- have a cell membrane ONLY, small food and waste vacuoles, mitochondria create energy through cellular respiration
chloroplast
contains chlorophyll which gives a plant its green color, uses sunlight to produce energy through photosynthesis
mitochondria
"powerhouse" of a cell, breaks down food to create energy through cellular respiration
phagocytosis
extensions of cytoplasm surround a particle and package it within a food vacuole, the cell then engulfs it, type of endocytosis
pinocytosis
cells take up liquid from the surrounding environment by forming tiny pockets along the cell membrane, type of endocytosis
reason fat-soluble particles can permeate easily
the cell membrane contains a lipid bi-layer
equilibrium
when the amount of water, particles, etc. entering the cell equals the amount exiting the cell
vacuole
very large in plant cells, stores water; smaller in animals cells, stores waste, sugar, water, etc.
phospholipids
similar to triglycerides, major difference is one fatty acid chain is replaced with phosphorus group that is charged, giving polarity. heads can interact with water and ions, make up cell membrane
how humans maintain homeostasis
sweating, getting goosebumps, shivering
examples of organ systems
endocrine system, respiratory system, excretory system, digestive system, cardiovascular system, muscular system, nervous system
cytoplasm
gel-like substance that holds the organelles within a cell and contains proteins and other particles