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cell review

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

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