Chapter 3: The Cellular Level Of Organization Flashcards
Cells
Are the basic, living, structures and functional units of the body
Cytosol
Fluid portion of cytoplasm, surrounds organelles
Cell 3 Main Parts
- Plasma membrane
- Cytoplasm
- Nucleus
Chromosome
A single molecule of DNA
Genes
Hereditary units that control most aspects of cellular structure and function.
Functions of Plasma Membrane
- 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.
Amphipathic
Have brother polar and non polar parts
Hydrophilic
Water loving
Hydrophobic
Water fearing
Glucocalyx
Extensive sugary coat formed by carbohydrate portions of glycolipids/proteins.
Ion Channels
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.
Channel Gated
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.
Osmosis
Type of diffusion in which there is net movement of a solvent through a selectively permeable membrane.
Tonicity
Is a measure of the solution’s ability to change the volume of cells by altering their water content.
Isotonic Solution
A solution in which a cell maintains it normal shape.
Hypotonic Solution
A solution that has a lower concentration of solutes.
Hemolysis
Water molecules enter the cells faster than they leave causing RBC to swell and burst.
Hypertonic Solution
A solution that has a higher concentration of solutes
Crenation
Water molecules move out of the cells faster than they enter, causing the cells to shrink.
Endocytosis
Materials move into a cell in a vesicle formed from the PM.
Exocytosis
Materials move out of a cell with the PM of vesicles formed inside the cell.
Vesicle
Small spherical sac. Transports substances to structures within a cell.
Phagocytosis
Form of Endocytosis.
Cell eating. Engulfs large solid particles.
Like: worn out cells, whole bacteria, viruses.
Phagocytes
2 Main Types
Body cells that carry out phagocytosis
1. Macrophages: located in body tissue
2.Neutrophils: Type of WBC
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.
Transcytosis
Vesicles undergo Endocytosis on one side of the cell, move across the cell and then undergo exocytosis on the opposite side.
Cytoskeleton
Network of protein filaments that extends throughout the cytosol.
Contain: micro filaments, intermediate filaments, microtubules
Microfilaments
Thinnest elements of the cytoskeleton. Generates movement, mechanical support.
Microvilli
Mechanical support for cell extension. They are microscopic finger like projections. They greatly increase the surface area of the cell.
Intermediate Filaments
Part of the cytoskeleton that is thicker than microfilaments, thinner than microtubules.
Exceptionally strong, help stabilize the position of organelles.
Microtubules
Largest of the cytoskeleton components.
Are long unbranched hollow tubes composed of mainly protein tubular.
Organelles
Specialized structures within a cell that have characteristics shapes and perform specific functions for cell growth, maintenance and reproduction.
Autophagy
Process by which entire worn out organelles are digested
Autophagosome
Vesicle created by the ER that enclose an organelle to be digested in autophagy.
Autolysis
Lysosomal enzyme that may destroy the the entire cell that contains them.
Apoptosis
Genetically programmed death of a cell.
Nuclear Envelope
Double membrane lipid bilayer, separates nucleus from the cytoplasm.
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.
Nucleoli
One or more spherical bodies inside the nucleus.
Function: producing ribosomes.
Chromatin
Complex of DNA and some RNA
Genome
The total genetic information carried in a cell or organism.
Nucleosome
Double stranded DNA wrapped twice around a core of 8 proteins. Is a bead on a string structure in chromatin.
Histones
Core of eight proteins help organize the coiling and folding of DNA
Linker DNA
String between beads, holds adjacent nucleosomes together
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.
Chromatids
A pair of condensed loops, before cell division, replicates DNA
Proteome
Refers to all of an organisms proteins
Base Triplet
A sequence of 3 nucleotides in DNA
Codon
DNA base triplet that is transcribes as a complementary sequence of 3 nucleotides
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.
Transcription
Proteins syntheses: DNA transcription begin at the promoter and ends at a terminator. Occurs in the nucleus.
Anticodon
Triplet of nucleotides
RNA polymerase
Catalyzes transcription of DNA
Promoter
Segment of DNA where transcription begins. Special nucleotide sequence located near the beginning of a gene.
Terminator
Special nucleotide sequence specifies the end of a gene.
Introns
Do not code for parts of proteins
Exons
Do code for segments of a protein
Polyribosomes
Several ribosomes that attach to the same mRNA
Somatic Cell
Any cell of the body other than a germ cell.
Germ Cell
A gamete (sperm or oocyte) or any precursor cell destined to become a gamete.
Mitosis
A cell that undergoes a nuclear division
Cytokinesis
Cytoplasmic division
Reproductive Cell Division
Mechanism that produces gametes, cells needed to form the next generation of sexually reproducing organism.
Meiosis
Process of 2 step division in which the number of chromosomes in the nucleus is reduced by half.
Cell Cycle
An orderly sequence of events in which somatic cell duplicates its contents and divides in two.
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.
Sex Chromosomes
One pair of chromosomes X and Y
Diploid (2n) cells
Somatic cells that contain 2 sets of chromosomes
Apoptosis
Normal type of cell death
Necrosis
Pathological type of cell death
Diploid
46 or two sets of 23
Haploid
One set of 23
Micrometers
Measure of units in which the size of cells are measured.
1 micrometer = 1 one millionth of a meter
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.
Plasma Membrane
A double membrane lipid bilayer. Forms the cells flexible outer surface. Separates internal and external environment.
Cytoplasm
Consists of all the cellular contents between PM and the Nucleus. Contains: cytosol and organelles.
Nucleus
Large organelle that houses most the cells DNA. Contains chromes and genes
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.
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
Potassium and Sodium in Cells
In most cells K+ has a higher concentration inside cell.
Na+ is present at higher concentration outside the cell
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.
Peripheral Proteins
Not as firmly embedded in the membrane. Either attached as polar heads or integral protiens.
Glycoproteins
Type of many integral proteins
Proteins with carbohydrate group attached to the ends that protrude into ECF.
Permeable
Membrane structure permits the passage of substance through it
Selective Permeability
Membrane permits some substance to pass more readily
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)
Concentration Gradient
Difference in the concentration of a chemical from one place to another
Electrical Gradient
Difference in electrical charge between two regions constitutes. Occurs across the plasma membrane.
Membrane Potential
Electrical gradient charge difference that occurs across the plasma membrane.
Electrical Chemical Gradient
The combined influence of the concentration gradient and the electrical gradient on movement of a particular ion.
Passive Process
Substance moves down its concentration or electrical gradient
Active Processes
Cellular energy is used to drive the substance uphill against its concentration gradient.
Energy form: ATP
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.
Cilia and Flagella
Cilia are numerous, short hair projections that extend from cell. Flagella are longer.
Microtubules are dominant component.
Ribosomes
Site of protein synthesis. Located within the mitochondria.
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.
Golgi Complex
Resembles a stable of pancakes.
Transport pathway for proteins that have been synthesized.
Lysosome
Membrane enclosed vesicle that form from the Golgi complex. Contain powerful digestive/hydrolysis enzymes that break down molecules known as autophagy.
Autophagy
Created by lysosomes. Digest and recycle worn out cell structure.
Peroxisomes
Contain several oxidases enzymes that can oxidize ( remove H+) from various organic substances.
Proteasomes
Function is continuous destruction of unneeded, damaged, or faulty proteins.
Mitochondria
Power house of cells. Generates most of the ATP through aerobic respiration.
Mitochondrial Cristae
Internal membrane in form of folds
Mitochondrial Matrix
Central fluid filled cavity. Does not contain phospholipids.
Plays an important role in apoptosis (cell death).
