Chapter 3: The Cellular Level Of Organization Flashcards
(104 cards)
1
Q
Cells
A
Are the basic, living, structures and functional units of the body
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Q
Cytosol
A
Fluid portion of cytoplasm, surrounds organelles
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Q
Cell 3 Main Parts
A
- Plasma membrane
- Cytoplasm
- Nucleus
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Chromosome
A
A single molecule of DNA
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Genes
A
Hereditary units that control most aspects of cellular structure and function.
6
Q
Functions of Plasma Membrane
A
- Acts as a barrier separating inside and outside of the cell.
- Controls the flow of substances into and out of the cell.
- Helps identify the cell to other cells.
- Participates in intercellular signing.
7
Q
Amphipathic
A
Have brother polar and non polar parts
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Q
Hydrophilic
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Water loving
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Q
Hydrophobic
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Water fearing
10
Q
Glucocalyx
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Extensive sugary coat formed by carbohydrate portions of glycolipids/proteins.
11
Q
Ion Channels
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Integral transmembrane proteins that contain poles or holes that allow passage of small, inorganic ions that are too hydrophilic to penetrate non polar interior of the lipid belayer.
12
Q
Channel Gated
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Channel is said to be gated when part of the channel proteins acts as a plug or gate changing shape in one way to open the pore and in another way to close it.
13
Q
Osmosis
A
Type of diffusion in which there is net movement of a solvent through a selectively permeable membrane.
14
Q
Tonicity
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Is a measure of the solution’s ability to change the volume of cells by altering their water content.
15
Q
Isotonic Solution
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A solution in which a cell maintains it normal shape.
16
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Hypotonic Solution
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A solution that has a lower concentration of solutes.
17
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Hemolysis
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Water molecules enter the cells faster than they leave causing RBC to swell and burst.
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Hypertonic Solution
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A solution that has a higher concentration of solutes
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Crenation
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Water molecules move out of the cells faster than they enter, causing the cells to shrink.
20
Q
Endocytosis
A
Materials move into a cell in a vesicle formed from the PM.
21
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Exocytosis
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Materials move out of a cell with the PM of vesicles formed inside the cell.
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Vesicle
A
Small spherical sac. Transports substances to structures within a cell.
23
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Phagocytosis
A
Form of Endocytosis.
Cell eating. Engulfs large solid particles.
Like: worn out cells, whole bacteria, viruses.
24
Q
Phagocytes
2 Main Types
A
Body cells that carry out phagocytosis
1. Macrophages: located in body tissue
2.Neutrophils: Type of WBC
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Pinocytosis
Or bulk phase Endocytosis
Cell drinking, tiny droplets of extracellular fluid is taken up.
PM folds inward and forms a vesicle containing a droplet of extracellular fluid.
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Transcytosis
Vesicles undergo Endocytosis on one side of the cell, move across the cell and then undergo exocytosis on the opposite side.
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Cytoskeleton
Network of protein filaments that extends throughout the cytosol.
Contain: micro filaments, intermediate filaments, microtubules
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Microfilaments
Thinnest elements of the cytoskeleton. Generates movement, mechanical support.
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Microvilli
Mechanical support for cell extension. They are microscopic finger like projections. They greatly increase the surface area of the cell.
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Intermediate Filaments
Part of the cytoskeleton that is thicker than microfilaments, thinner than microtubules.
Exceptionally strong, help stabilize the position of organelles.
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Microtubules
Largest of the cytoskeleton components.
Are long unbranched hollow tubes composed of mainly protein tubular.
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Organelles
Specialized structures within a cell that have characteristics shapes and perform specific functions for cell growth, maintenance and reproduction.
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Autophagy
Process by which entire worn out organelles are digested
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Autophagosome
Vesicle created by the ER that enclose an organelle to be digested in autophagy.
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Autolysis
Lysosomal enzyme that may destroy the the entire cell that contains them.
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Apoptosis
Genetically programmed death of a cell.
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Nuclear Envelope
Double membrane lipid bilayer, separates nucleus from the cytoplasm.
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Nuclear Pores
Openings that extend through nuclear envelope. Allow substances of all sizes to pass from the nucleus to the cytoplasm. Allows ribosomes and proteins to pass.
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Nucleoli
One or more spherical bodies inside the nucleus.
Function: producing ribosomes.
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Chromatin
Complex of DNA and some RNA
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Genome
The total genetic information carried in a cell or organism.
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Nucleosome
Double stranded DNA wrapped twice around a core of 8 proteins. Is a bead on a string structure in chromatin.
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Histones
Core of eight proteins help organize the coiling and folding of DNA
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Linker DNA
String between beads, holds adjacent nucleosomes together
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Chromatin Fiber
Created when histones promote coiling of nucleosomes into large diameter fiber, that folds into large loops.
Created in cells that do not divide.
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Chromatids
A pair of condensed loops, before cell division, replicates DNA
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Proteome
Refers to all of an organisms proteins
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Base Triplet
A sequence of 3 nucleotides in DNA
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Codon
DNA base triplet that is transcribes as a complementary sequence of 3 nucleotides
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Genetic Code
Set of rules that relate the base triplet sequence of DNA to the corresponding codons of RNA and the amino acids they specify.
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Transcription
Proteins syntheses: DNA transcription begin at the promoter and ends at a terminator. Occurs in the nucleus.
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Anticodon
Triplet of nucleotides
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RNA polymerase
Catalyzes transcription of DNA
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Promoter
Segment of DNA where transcription begins. Special nucleotide sequence located near the beginning of a gene.
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Terminator
Special nucleotide sequence specifies the end of a gene.
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Introns
Do not code for parts of proteins
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Exons
Do code for segments of a protein
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Polyribosomes
Several ribosomes that attach to the same mRNA
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Somatic Cell
Any cell of the body other than a germ cell.
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Germ Cell
A gamete (sperm or oocyte) or any precursor cell destined to become a gamete.
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Mitosis
A cell that undergoes a nuclear division
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Cytokinesis
Cytoplasmic division
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Reproductive Cell Division
Mechanism that produces gametes, cells needed to form the next generation of sexually reproducing organism.
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Meiosis
Process of 2 step division in which the number of chromosomes in the nucleus is reduced by half.
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Cell Cycle
An orderly sequence of events in which somatic cell duplicates its contents and divides in two.
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Homologous Chromosomes
Two chromosomes that make up each pair:
Human cells contain 23 pairs of chromosomes. One member of each pair is inherited form each parent.
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Sex Chromosomes
One pair of chromosomes X and Y
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Diploid (2n) cells
Somatic cells that contain 2 sets of chromosomes
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Apoptosis
Normal type of cell death
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Necrosis
Pathological type of cell death
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Diploid
46 or two sets of 23
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Haploid
One set of 23
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Micrometers
Measure of units in which the size of cells are measured.
1 micrometer = 1 one millionth of a meter
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Shapes of Cells
Can vary and is related to its function.
Can be round, oval, flat, cubed shaped, column shaped, elongated, star shaped, cylindrical or disc shaped.
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Plasma Membrane
A double membrane lipid bilayer. Forms the cells flexible outer surface. Separates internal and external environment.
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Cytoplasm
Consists of all the cellular contents between PM and the Nucleus. Contains: cytosol and organelles.
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Nucleus
Large organelle that houses most the cells DNA. Contains chromes and genes
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Fluid Mosaic Model
Best way to describe the plasm membrane.
Molecular arrangement of PM resemble a continually moving sea of fluid lipids that contain a mosaic of many different proteins. Some proteins float freely other are anchored at specific locations.
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Structure of Plasma Membrane
Lipid bilayer is basic structural frame work.
Double layers made up of 3 types of lipid molecules
1. Phospholipid: 75% contains PO4
2. Cholesterol: 20 % steriod with attached OH group
3. Glycolipids: 5% lipid with attached carbohydrate group
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Potassium and Sodium in Cells
In most cells K+ has a higher concentration inside cell.
Na+ is present at higher concentration outside the cell
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Integral Proteins
Extend into and through the lipid bilayer and are firmly embedded to it.
Most are: transmembrane proteins-they span entire lipid bilayer and protrude into both cytosol and ECF.
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Peripheral Proteins
Not as firmly embedded in the membrane. Either attached as polar heads or integral protiens.
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Glycoproteins
Type of many integral proteins
Proteins with carbohydrate group attached to the ends that protrude into ECF.
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Permeable
Membrane structure permits the passage of substance through it
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Selective Permeability
Membrane permits some substance to pass more readily
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Lipid Bilayer Permeability
Highly permeable to non polar molecules: O2, CO2, steroids
Moderately Permeable to small uncharged molecules: water, urea (waster product of amino acids)
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Concentration Gradient
Difference in the concentration of a chemical from one place to another
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Electrical Gradient
Difference in electrical charge between two regions constitutes. Occurs across the plasma membrane.
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Membrane Potential
Electrical gradient charge difference that occurs across the plasma membrane.
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Electrical Chemical Gradient
The combined influence of the concentration gradient and the electrical gradient on movement of a particular ion.
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Passive Process
Substance moves down its concentration or electrical gradient
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Active Processes
Cellular energy is used to drive the substance uphill against its concentration gradient.
Energy form: ATP
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Centrosome
Organelle.
Microtubules organization center. Found near the nucleus, consists of pericentriolar matrix. This matrix is composed of protein tubulin, plays critical role in cell division.
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Cilia and Flagella
Cilia are numerous, short hair projections that extend from cell. Flagella are longer.
Microtubules are dominant component.
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Ribosomes
Site of protein synthesis. Located within the mitochondria.
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Endoplasmic Reticulum
Network of membranes in the form of flattened sacs.
1. Rough ER: Proteins synthesized by ribosomes enter the ER for processing and sorting.
2. Smooth ER: extends from rough ER. Does not have ribosomes. Synthesizes fatty acids, steroids.
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Golgi Complex
Resembles a stable of pancakes.
Transport pathway for proteins that have been synthesized.
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Lysosome
Membrane enclosed vesicle that form from the Golgi complex. Contain powerful digestive/hydrolysis enzymes that break down molecules known as autophagy.
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Autophagy
Created by lysosomes. Digest and recycle worn out cell structure.
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Peroxisomes
Contain several oxidases enzymes that can oxidize ( remove H+) from various organic substances.
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Proteasomes
Function is continuous destruction of unneeded, damaged, or faulty proteins.
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Mitochondria
Power house of cells. Generates most of the ATP through aerobic respiration.
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Mitochondrial Cristae
Internal membrane in form of folds
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Mitochondrial Matrix
Central fluid filled cavity. Does not contain phospholipids.
Plays an important role in apoptosis (cell death).
