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Biology Chapter 3
Cells
37
Biology
Undergraduate 1
01/31/2011

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Term
Cell Theory
Definition
1. All living organisms made of one or more cells 2. Cells are the fundamental unit of life 3. All cells come from preexisting cells
Term
What are the features common to all cells?
Definition
DNA, proteins (that carry out the cells work), RNA, ribosomes, cytoplasm, cell membrane, and small size
Term
Phospholipid
Definition
composes cell membranes, made of lipids and phosphates, 3 carbon glycerol molecule, phosphate end hydrophilic, lipid end hydrophobic
Term
What are the four components of the cell membrane?
Definition
phospholipid molecules, cholesterol molecules, proteins, and glycocalyx
Term
How do the hydrophobic and hydrophilic ends of phospholipids create the phospholipid bilayer?
Definition
The hydrophilic ends create the area exposed to the water medium outside and inside the cell, and the hydrophobic tails face each other away from the water
Term
Sterols (Cholesterol Molecules) - as a part of the membrane
Definition
Have a hydrophilic and hydrophobic region, the hydrophobic region enhances the phospholipid bilayers ability to keep water from passing through. Cholersterol also helps stop lipids from solidifying due to changes in temperature
Term
What does it mean when the cell membrane is called a Fluid Mosaic?
Definition
that proteins and phospholipids are free to move laterally within the bilayer
Term
Proteins in the membranes
Definition
Integral proteins imbedded in the phospholipid bilayer, and peripheral proteins on either side of the phospholipid bilayer. Proteins make membrane an active player
Term
What are some diverse functions of proteins in the membrane?
Definition
Transport Proteins create passageways, Enzymes speed up chemical reactions, recognition proteins help body recognize its own cells, adhesion proteins enable cells to stick to one another, and receptor proteins bind to molecules outside of the cell trigger a reaction inside of the cell.
Term
Glycocalyx
Definition
sugar side cells on the cell membrane that in prokaryotes help cell from drying out and protects the cell from harm and in eukaryotes it is part of the communication system and prevents cells from dividing when they shouldn't
Term
Signal Transduction
Definition
When a cell recieves an exernal message and coverts it into an internal signal, this stimulates specific functions in the cell
Term
Nucleoid
Definition
It is where DNA is located in prokaryotic cells
Term
What are nuclear pores?
Definition
Holes in the nuclear envelopes where mRNA molecules exit, vary busy millions of proteins and mRNA molecules pass in and out each minute
Term
Nucleolus
Definition
Dense spot in the nucleus that assembles the components of ribosomes
Term
Endoplasmic Reticulum
Definition
a network of sacs and tubules composed of membranes - literally means network within the cytoplasm, has both rough and smooth parts of the network
Term
Rough ER
Definition
rough part near nucleus where enzymes fold and modify proteins
Term
Smooth ER
Definition
synthesizes lipid and other membrane components, and also detoxes drugs and poisons
Term
Vesicles
Definition
where the lipids and proteins made by the Er exit the organelle
Term
Golgi Apparatus
Definition
stack of flat, membrane-enclosed sacs that function as a proecessing centers. Proteins complete their intricate folding here and become functional, enzymes here also attach carbs to proteins or lipids
Term
Lysosomes
Definition
organelles containing enzymes that dismantle captured bacteria, worn-out organelles, and debris. The enzymes inside are manufactured by rough ER. they fuse with vesicles carrying debris and break them down
Term
What is the purpose of a large central vacuoles in plant cells?
Definition
the watery solution it contains has enzymes that degrade and recycle molecules, much like lysosomes in animal cells.
Term
Peroxisomes
Definition
organelles in eukaryotes that contains several types of enzymes that dispose of toxic substances, break down fatty acids, and produce cholesterol and some other lipids
Term
Mitochondria
Definition
use cellular respiration to extract energy from food needed o produce proteins secrete, and perform the chemical reactions in the cell
Term
Cristae
Definition
folds of inner membranes that contain enzymes that catalyze the biochemical reactions of cellular respiration
Term
What is the cytoskeleton and what are some of its functions?
Definition
it is an intricate network of internal protein tracks and tubules. It is a transportational system, it maintains the three dimensional shape of the cell, it enables movement, cell division, and cell connection
Term
Chromatin
Definition
uncoiled lengths of DNA in the nucleus
Term
What are the three major protein components of the cytoskeleton?
Definition
Microtubules, microfilaments, and intermediate filaments
Term
Microtubules
Definition
composed of a protein called tubulin which determines how long it is, it is a trackway to move cells rapidly, examples include cilia and flagella
Term
Microfilaments
Definition
long thin rod composed of the protein actin, networks of this provide the machinary to move if provoked by a signal, provides strength to survive stretching and compression, and helps anchor one cell to another
Term
Intermediate filaments
Definition
made up of different proteins in specialized cell types, resist mechanical stress, helps bind some cells together
Term
What cells do cell walls surround
Definition
almost all bacteria, archaea, fungi, algae, and plants
Term
What are some functions of the cell wall?
Definition
barrier, imparts shape, volume, prevents bursting, and interacts with other cells to see how a cell should specialize
Term
Plasmademota
Definition
channels that connect adjacent cells and allow them to communicate
Term
What are the three different kinds of junctions in animal cells?
Definition
tight junctions, anchoring junctions, and gap junctions
Term
tight junctions
Definition
fuses cells together forming an impermeable barrier between them
Term
Anchoring Junctions
Definition
connects adjacent cells by linking intermediate filaments in a single spot
Term
Gap Junctions
Definition
protein channels that link the cytoplasm of adjacent cells allowing exchange of ions, nutrients, and other small molecules
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