Chapter 3 Flashcards
The cell is
The structural and functional unit of all living organisms
Cell theory
Schleiden and Schwanna in 1838
The cell is the basic unit of life
All organisms are composed of cells
All cells are derived from other cells
3 major areas of the cell
Cell membrane
Nucleus
Cytoplasm with its organelles
Father of the cell
Robert hook
What is the plasma membrane composed of
Mostly lipid, two major phospholipids and cholesterol
What controls fluidity of the plasma membrane
Cholesterol
Phospholipid bolster
Double layer producing hydrophilic heads and hydrophobic tails
Fluid mosaic model
Neither rigid nor static but dynamic and flexible. Self healing
Membrane potential
Cell membrane is polar as there is a separation of charge across it. Membrane potential is the separation of charge
Charge inside and outside the cell
Positive outside negative inside
Functions of plasma membrane
Regulates what enters and leaves the cell
Itneractions with other molecules occur at the plasmalemma
Delineates intracellular from extra cellular
two categories of proteins of the cell membrane
Peripheral/extrunsic or integral/intrinsic
Peripheral/extrunsic proteins
Attached to either the inner or outer membrane surface. Do not go all the way though the membrane
Integral/inteinsic proteins
Embedded throughout the membrane. Extend from one side to the other. Ex: channel proteins
Membrane proteins
Market molecules
Attachment proteins
Transport proteins - channel, carrier, pumps
Receptor molecules
Market molecules
Mostly glycolipids and glycoproteins - the carbohydrate portions stuck up on extracellular side of cell to allow for cell recognition
Ex- immunity, sperm, antigen markers
Attachment proteins
Proteins in the cell membrane that serve as attachment sites for other cells or extracellular molecules
Transport proteins
Allow ions or molecules to pass from one side of the membrane to the other down the gradient.
Three characteristics with regard to membrane support with transport proteins
Specificity (each carrier binds to only one molecule)
Competition (similar shape compounds might compete for site)
Saturation (rate is limited when all sites are filled)
Channel proteins
Like a tube stuck through the membrane to allow passage of ions or small molecules. Can be open or closed.
Nongated channels
Always open. Ions move down their gradient. Also called leak channels.
Gated channels
Open due to a stimulus
Ligand gated- open when a molecule binds
Voltage gated- open due to a change in charge
Carrier proteins
Move ions from one side to the other with a specific binding shape that changes shape to transport.
Pumps (atp powered)
Move ions or small molecules from one side of the other against their gradient. Ex. Na+/K+ pump
Receptor molecules
Proteins that have molecules on the cell surface that bind a specific molecule. The molecule binding is called the messenger
High concentration of what inside the cell
Enzymes, proteins, glycogen, and potassium ions
High concentration outside the cell
Sodium, calcium and chloride ions
Passive membrane transport
Does not require atp and includes diffusion, osmosis, and facilitation diffusion.
Diffusion
Movement of solutes from an area of high concentration to an area of low across the membrane.
Diffusion
Movement of solutes from an area of high concentration to an area of low across the membrane.
Rate of diffusion influenced by
Magnitude of concentration gradient, temp of solution, the size of the diffusing molecules, and the viscosity of the solvent
Viscosity
Measure of how easily a liquid flows. Diffusion moves slower in higher viscosity
Osmosis
Diffusion of water across a selectively permeable membrane from an area of low solute to an area of high solute
Isosmotic
Solutions with same concentration of solute particles
Hypertonic solution
High concentration of solutes
Hypotonic solution
Low concentration of solutes
Crenation
Cell shrinks
Lysis
Cell swells
Facilitated diffusion
Mediated transport using carrier proteins to carry something down the concentration gradient and across. No atp required
Active transport
Transport requiring atp to move things against the gradient
Secondary active transport
Transport of ion out of cell setting up a gradient which is used to transport a different compound actoss
Vesicular transport
Bringing things in or out by vesicles
Endocytosis
And exocytosis
Endocytosis
Brings things in by pinching off membrane
Phagocytosis: cell eating
Pinocytosus: cell drinking
Exocytosis
Sending particulars out of the cell. These require energy
Cytoplasm makeup
Half organelles and half cytosol
What does the cytosol consist of
Fluid portion, cytoplasmic inclusions (aggregates of chemicals) and the cytoskeleton
Types of protein structures in cytoskeleton
Microtubules
Actin filaments
Intermediate filaments
Supports and allows the cell to move and change shape
Ribosomes
Site of protein synthesis.
Consist of rRNA and proteins.
Endoplasmic reticulum
Membranous pathways within cell
Rough - ribosomes attached and site of protein synthesis for those destined for export of the sell. Transport system to golgi.
Smooth - tubules where lipids are produced
Golgi apparatus
Flatted membranous sac which modify, package and distribute proteins and lipids for secretion out of the cell
Lysosome
Contain digestive enzyme and are used to digest ingested pathogens or dead organelles
Peroxisome
Membrane bound vesicles that detoxify harmful chemicals like alcohol
Mitochondria
Double membrane bound. Inner membrane is the crustae and the site of ATP production via the Krebs cycle. Has own DNA — can trace maternal heritage
Centrioles
Cylindrical organelles made of tubulin which are the center for formation of micro tubules. Used for cell division
Spindle fibers
Microtubules extending from centrioles to chromosomes, assists in separating chromosomes during mitosis
Cilia
Extensions of plasma membrane. These move materials over the surface
Flagellum
Extension of plasma membrane that functions for cell mobility. Ex. Sperm
Microvilli
Extensions of plasma membrane that act to increase surface area for absorption
Chromatin
In the nucleus. DNA + associated histones.
Duplicates and condenses down to chromosomes prior to mitosis.
Nucleolus
Within the nucleus that is fhe site for rRNA synthesis
Triplet
Every three nucleotides on a dna strands and codes for a single amino acid in the protein to be made
Gene
All of the triplets that code for synthesis of a specific protein
Gene expression
The production of proteins from the code stored in dna
Parts of protein synthesis
Transcription then translation
Transcription
First step. Copy of dna recipe copied onto an mRNA molecule.
Translation
Occurs in cytoplasm at the ribosomes when the recipe on mRNA is translated and built with the help of tRNA
Codon
A group f three nucleotides on the mRNA that are complementary to the triplets
Ends transcription
Terminator sequence
Anticodon
Group of three nucleotides on tRNA that are complementary to those on the mRNA
Somatic
All cells in the body are somatic except for egg and sperm. Chromosomes exist in pairs (diploid state)
Germ cell
Egg and sperm
Chromosomes exist singly (haploid state(
Meiosis
Specialized cell division in eggs and sperm where four daughter cells are formed, each with 1/2 the diploid number of chromosomes (only 24 chromosomes not in pairs)
How many chromosomes are in human somatic cells
46 chromosomes in 23 pairs
Father of genetics
Gregor Mendel
Mendelian genetics
Cornerstone of the study of how traits are passed from parents to offspring
Genotype
The genes an individual has for given traits
Phenotype
Expression of general
Alleles
alternative forms of genes
Autonomies
Number chromosomes
Karyotype
Display of entire chromosome makeup
Complete dominance
One allele masks the other
Incomplete dominance
Dominant allele does not completely mask
Codominance
Neither allele is completely dominant and both are expressed. Blood typing is an example of
Sex linked traits
Traits carried on the X or y chromosome. Hemophilia is an x-linked trait
