Laakso Ch.7

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cell theory
a fundamental concept of biology that states:
- all living things are made up of cells
- cells are the basic unit of structure and function in living things
- new cells are produced from existing cells
light microscopes
this allows light to pass through a specimen and uses 2 lenses to form an image, they produce clear images of objects only to a magnification of about 1000 times
electron microscopes
these use beams of electrons, not light, that are focused by magnetic fields to see cell structures as small as one millionth of a meter and offers a much higher resolution than light microscopes
cell membrane
the thin, flexible barrier that surrounds all cells
regulates what enters and leaves the cell and also protects and supports the cell
nucleus
a large, membrane-enclosed structure that contains the cells genetic material in the form of DNA; it controls many of the cells activities because it is the control center of the cell
it contains nearly all the cells DNA and, with it, the coded instructions for making proteins and other important molecules
eukaryotes
cells that enclose their DNA in the nuclei
these cells are generally larger and more complex than prokaryotic cells
most contain dozens of structures and internal membranes and are highly specialized
prokaryotes
cells that do not enclose their DNA in the nuclei
these cells are also generally smaller and simpler than the eukaryotic cells
despite their simplicity, they grow, reproduce, and respond to their environment, and some even move by gliding along surfaces or swimming through liquids
- bacteria are an example of these
1. nucleus
2. cytoplasm
eukaryotic cell divided into two parts:
cytoplasm
the fluid portion of the cell outside of the nucleus
organelles
structures that act as if they are specialized organs
literally "little organs"
nuclear envelope
this is dotted with thousands of nuclear pores, which allow material to move into and out of the nucleus
RNA
molecules moving to and from the rest of the cell
vacuoles
large, sac like, membrane-enclosed structures that store materials such as water, salts, proteins, and carbohydrates
vesicles
these are contained in eukaryotic cells and are smaller, membrane-enclosed structures used to store and move materials between cell organelles, as well as to and from the cell surface
lysosomes
small organelles filled with enzymes that function as the cells clean up crew. they perform the vital function of removing "junk" that might otherwise accumulate and clutter up the cell
cytoskeleton
a network of protein filaments that give eukaryotic cells their shape and internal organization
certain parts also help to transport materials between different parts of the cells much like conveyor belts that carry materials from one part of the factory to another
microfilaments and microtubules
two of the principal protein filaments that makeup the cytoskeleton
ribosomes
small particles of RNA and protein found throughout the cytoplasm in all cells
they produce proteins by following coded instructions that come from DNA
rough endoplasmic reticulum
the portion of the endoplasmic reticulum involved in synthesis of proteins
given this name because o the ribosomes found on the surface
newly made proteins leave these ribosomes and are inserted here where they may be chemically modified
smooth endoplasmic reticulum
the other portion of the endoplasmic reticulum where ribosomes are not found on the surface
in many cells, this contains collections of enzymes that perform specialized tasks, including synthesis of membrane lipids and the detoxification of drugs(toxins and foreign substances)
golgi apparatus
this modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell
proteins are "shipped" to their final destination inside or outside the cell
mitochondria
nearly all eukaryotic cells contain this, including plants
the power plants of the cell
they convert the chemical energy stored in food into compounds that are more convenient for the cell to use
chloroplasts
they capture the energy from sunlight and convert it into food that contains chemical energy in a process called photosynthesis
lipid bilayer
the composition of nearly all membranes is a double layered sheet called a ______, which gives cell membranes a flexible structure and forms a strong barrier between the cell and its surroundings
when lipids are mixed with water, their hydrophobic fatty acid "tails" cluster together while their hydrophilic "heads" are attracted to water - resulting in this
cell wall
a strong supporting layer around the membrane
passive transport
the movement of materials across the cell membrane without using cellular energy
diffusion
the process by which particles move from an area of high concentration to an area of lower concentration
the driving force behind the movement of many across the cell membrane
facilitated diffusion
the process where molecules that cannot directly diffuse across the membrane pass through special protein channels
osmosis
an example of facilitated diffusion
the diffusion of water through a selectively permeable membrane
this involves the movement of water molecules from an area of higher concentration to an area of lower concentration
isotonic
means "same strength"
when the concentration is the same on both sides of the membrane
hypertonic
means "above strength"
the more concentrated sugar solution at the start of the experiment compared to the dilute sugar solution
hypotonic
means "below strength"
active transport
the movement of materials against a concentration difference
this requires energy
homeostasis
just like other living things, unicellular organisms much achieve this
a relatively constant internal physical and chemical condition
tissue
a group of similar cells that performs a particular function
organ
to perform complicated tasks, many groups of tissues work together as this
organ system
a group of organs that work together to perform a specific function
ex: the stomach, pancreas, and intestines work together as the digestive system
cell--->tissue--->organ--->organ system
cell organization
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