Chapter 3.2 Flashcards
The three major parts of a cell?
Nucleus
Cytoplasm
Cell Membrane
Nuclear Envelope
The nucleus is innermost and is enclosed by a thin membrane
Selectively Permeable
A membrane that controls the entrance and exit of substances, allowing some in while excluding others
Signal Transduction
When the cell membrane allows the cell to receive and respond to incoming messages
Cell membrane is mainly composed of roughly
equal numbers of lipid and protein molecules, with fewer carbohydrates
Basic framework of the cell membrane is
a double layer, or bilayer, of phospholipid molecules
Bilayers form so that
hydrophilic heads from intracellular and extracellular surfaces of the membrane, and hydrophobic tails make up the middle portion of the membrane
What can pass through the phospholipid bilayer easily?
Molecules soluble in lipids, such as oxygen, CO2, and steroid hormones
Integral Proteins
Form pores, channels, and carries in the cell membrane; transduce signals
Enzymes..
catalyze chemical reactions
cellular adhesion molecules
enable cells to stick to each other
Calcium Channels do what?
Chest Pain
Sodium channels do what?
Local Anesthetics
Chloride Channels do what?
Muscle Relaxants
Potassium Channels do what?
Antidiabetics
Some of Peripheral Proteins functions?
Receptors, Others are Enzymes, and many are parts of signal transduction pathways
Carbohydrate groups attached to some peripheral proteins form
glycoproteins that branch from a cells surface, enabling cells to recognize and interact with each other
Glycoproteins can also
mark the cells of an individual as “self” and distinguish differentiated cell types
Cellular Adhesion Molecules
guide cells on the move
Cytoskeleton
Cytoplasm contains abundant protein rods and tubules that form a supportive framework
Ribosomes are composed of
protein and RNA
Ribosomes provide
structural support and enzymatic activity to link amino acids to synthesize proteins
What is the Endoplasmic Reticulum?
Complex organelle composed of membranous flattened sacs, cylinders, and fluid-filled bubblelike sacs called vesicles
Part of the ER participates in
the synthesis of protein and lipid molecules.
Smooth ER lack..
ribosomes
Along the Smooth ER are
enzymes that are important in synthesizing lipids, absorbing fats from the digestive tract, and breaking down certain drugs.
Lipids are synthesized in the smooth ER and are
added to proteins arriving from the rough ER
Vesicles are
membranous sacs that store or transport substances within a cell or between cells
What is Vesicle Trafficking
The transport of substances into and out of cells by fleets of vesicles
What is the Golgi Apparatus
A stack of five to eight flattened, membranous sacs called cisternae that resemble a stack of panckaes
What does the Golgi Apparatus do?
The organelle refines, packages, and transports proteins synthesized on the rough ER.
When glycoproteins reach the outermost layer,
they are packaged in bits of golgi apparatus membrane, which bud off and form transport vesicles
Exocytosis
When such a vesicle may then move to the cell membrane, where it fuses and releases its contents to the outside of the ell as a secretion
Cellular Respiration
When enzymes and others dissolved in the fluid in the mitochondrion called the matrix, control many of the chemical reactions that release energy from glucose and other nutrients
How is ATP made?
When the mitochondrion captures and transfers this newly released energy into special chemical bonds of the molecule
A typical cell has how many mitochondria?
Has about 1,700 mitochondria
What are lysosomes?
They are “garbage disposals” of the cell, where enzymes dismantle debris.
What is autophagy?
The process of a cell disposing of its own trash, which also means “eating self”
Lysosomes bud off of sections of
golgi membrane
Lysosome enzymes break down
proteins, carbohydrates, and nucleic acids
What are peroxisomes?
Membranous sacs that resemble lysosomes in size and shape.
What enzyme do peroxisomes contain?
Peroxidases, and Catalase
What do Peroxidases do?
They catalyze metabolic reactions that release hydrogen peroxide, which is toxic to cells
What does Catalase do?
Decomposes hydrogen peroxide
What do Peroxisomes do?
Synthesis of bile acids used in fat digestion
Breakdown of lipids called very-long-chain fatty acids
Degradation of rare biochemicals
Detoxification of alcohol
What are microfilaments?
They are tiny rods of the protein actin that form meshworkds or bundles and provide cellular motility. . Associated with the inner surface of the cell membrane aid cell motility
What are microtubulutes?
Long, slender tubes with diameters two or three times greater than those of microfilaments. Composed of tubulin, and enables maintain cell shapes
Wht are intermediate filaments?
They are composed of any of several types of proteins. Make protein called keratins and abundtant in the oter skin layer.
What is a centrosome?
A structure in the cytoplasm near the nucleus. COnsists of two centrioles and are there to produce spindle fibers that pull on and distribute chromosomes.
What are cilia?
They extend from cells. Move in coordianted “to-andfro” manner so that rows of cilia beat in succession, generating a wave that sweeps across the surface.
What are microvilli?
They are tiny extensions of the cell membrane that absorb substances. They are built of actin, not tubilin molecules
The extemely long molecules of DNa are complexed with
proteins to form fibers called chromatin
Nuclear pores let out
molecules of messenger RNA that carry genetic information, but does not let out the DNA, which must stay in the nucleus to maintain the genetic information
Chromatin consists of
the cells 46 chromosomes.
What is a nucleolus?
Small dense body largely composed of RNA and protein. No surrounding membrane and formed in specialized regions of certain chromosomes
Cell Membrane Structure
Membrane mainly composed of protein and lipid molecules
Cell Membrane Function
Maintains integrity of the cell, controls the passage of materials into and out of the cell, and provides for singla transfuction
Ribosome Structure
Particles composed of protein and RNA molecules
Ribosome Function
Synthesize proteins
Endoplasmci Reticulum Structure
COmplex of connected, membrane-bound sacs, canals, and vesicles
Endoplasmic Reticulum Function
Transports materials witin the cell, provides atttachment for ribosomes, and synthesizes lipids
Vesicles Structture
Membranous Sacs
Vesicles Function
Contains substances that recently entered the cell, store and transport synthesized molecules within the cell and to other cells
Golgi Apparatus Structure
Group of flattened, membranous sacs
Golgi Apparatus Function
Packages and modifies protein molecules for transport nd secretion
Mitochondria Structure
Membranous sacs with inner partitions
Mitochondria Function
Release energy from food moleules and conver the energy into a useable form (ATP)
Lysosome Structure
MEmbranous sacs
Lysosome Function
Contain enzymes that break down worn cellular parts or substances that enter cells
Peroxisomes Structure
Membranous Sacs
Peroxisomes Functtion
Contains enzymes called peroxidases, important in the breakdown of many organic molecules
Centrosome Structure
Nonmembranous structure composed of two rodlike centrioles
Centrosome Function
Helps distribute chromosomes to a new cell during cell divison, initiates formation of cilia
Cilia Structure
Motile projections attached to basal bodies beneath the cell membrane
Cilia Function
Some cilia propel fluids over cell surface, others are sensory
Flagellum Structure
Projection attached to a basal body beneath the cell membrane
Flagellum Function
Enables sperm cells to move
Microfilaments and Microtubules Structure
Thin rods and tubulues
Microfilaments and Microtubules Function
Support cytoplasm, help move substances and organeles within the cytoplasm
Nuclear Envelope Structure
Selectively permeable double membrane that sesparates the nuclear contents from the cytoplasm
Nuclear Envelope Function
Maintains the integrity of the nucleus and controls passage of materials between the nucleus and cytoplasm
Chromatin Structure
FIbers composed of protein and DNA molecules
Chromatin Function
Carries information for synthesizing proteins
Nucleolus Structure
Dense, nonmembranous body composed of protein and RNA molecules
Nucleolus Function
Site of ribosome formation
