Chapter 3 Flashcards
Prokaryotic Cells
Lack nuclei
DNA is not surrounded by membranous envelope
Bacterial chromosome or nucleoid- DNA that occurs in the form of a large circular molecule
Lack organelles
Eukaryotic Cells
Chromosomes surrounded by envelope
DNA is linear and bounded to histones
Has organelles
Protoplast
Unit of protoplasm inside cell wall, includes cytoplasm and nucleus
Plasma membrane function
Separates in/external environment
Mediates transport of substances
Synthesize cellulose
Maintains homeostasis within body
Tonoplast
Membrane surrounding vacuoles
Plant cell
Cytoplasmic streaming or cyclists
Facilitates the transport of materials within the cell and between the cell and it’s environment
Nucleus Function
Controls which and even proteins are to be produced
Stores genetic info with can be passed
Nuclear Genome
The Total genetic information stored in the nucleus
Endoplasmic reticulum
A complex system of membranes that play a central role in cellular biosynthesis
Number or chromosomes
Haploid- single set of chromosomes, n
Diploid- double set of chromosomes, 2n
Polyploid- more than 2 sets of chromosomes, 3n 4n 5n etc
Nucleoli; nucleolus (singular)
Each nucleolus Contains high concentrations of proteins along with large loops of DNA (nucleolar organizer regions), this side of formation of ribosomal subunits
Ribosomes
17-23 nanometers
Consist of protein and RNA
*more protein than RNA
RNA is 60% of the mass
Each ribosome consists of a large and small subunit, produce in nucleolus and exported to the cytoplasm to be assembled into a ribosome
Located in cytoplasm, endoreticulum, smaller ones in plastids and mitochondria
Polysomes is polyribosomes
The clusters or aggregates that ribosomes activate protein synthesis
Attached to the outer surface of nuclear envelope
Plastids
Photosynthesis and storage
Types: chloroplasts, chromoplasts, leucoplasts
Surrounded by:
Thylakoids- flattened sacs
Stroma- homogeneous matrix
Chloroplasts
Sites of photosynthesis, contain chlorophylls, and carotenoid pigments (yellow, orange)
In plants usually disk shaped 4-6 micrometers
A single mesophyll cell contain 40-50 chloroplasts (square millimeter 500,000)
Grana- stacks of disks
Contain starch grains and small lipid oil droplets
Semiautonomous- can synthesize some of their own polypeptides
Chromoplasts
Pigmented plastics, lack chlorophyll and retain carotenoid pigments (yellow, orange, red)
Attractant and plays a role in cross pollination
Proplastids
Small, colorless, pale green, undifferentiated plastids in meristematic cells of roots and shoots
Precursors of chloroplasts, chromoplasts, or leucoplasts
If they contain prolamellar bodies they’re called etioplasts
Etioplats
Form in leaves of plants in the dark
When exposed to light, etioplasts develop into chloroplasts and the membranes develop into chloroplasts
Mitochondria
Responsible for respiration, biosynthesis of amino acid’s, vitamin cofactors, fatty acid’s, and programmed cell death with the release of cytochrome c and mitochondrial swelling
Semiautonomous
The matrix contains protein RNA, DNA, small ribosomes and various solutes
Peroxisomes
Play an important role in photo respiration, that consumes oxygen and release carbon dioxide
Glyoxysomes- contains the enzymes necessary for the conversion of stored fat to sucrose during germination in many seeds
Inconvertible
No DNA nor ribosomes
Vacuole
Contain cell sap (water), Ca2+, K+, Cl-,Na+, and HPO4 2-, sugars, organic acids, and amino acids
Storage compartment for sugars, primary metabolites, and chlorophyll
Endoplasmic Reticulum
Rough ER- cells that store proteins have an abundant, flattened sacs, or cisternae, polysomes on surface
Smooth ER- lacks ribosomes and is largely tubular in form, involved in lipid synthesis
Cortical ER- regulates the level of calcium ions in Cytosol (interconnected by plasmodesmata)
Serves as a communication system within the cell and as a system for channeling materials such as proteins and lipids
Golgi bodies
Involved in the synthesis and secretion of noncellulosic polysaccharides destined for incorporation into the cell wall, also process and secrete glycoproteins from the rough ER via transition vesicles
Geico porches are transported stepwise across the stack to maturing face by means of shuttle vesicles to be delivered to the vacuole for secretion
Cytoskeleton
Consist of Microtubules and Actin filaments ~intermediated filament
Microtubules-Serve to direct secretory Golgi Vesicles containing noncellulosic cell wall substances toward the developing wall; they also make up the spindle fibers that aid in chromosome movement (24 nm)
Dynamic instability
The breakdown, we formation, and rearrangement into new configurations of microtubules during differentiation
Actin filaments
Composed of actin (5-7 nm)
Involved in cell wall the position, tip growth of pollen tubes, movement of the nucleus before and following cell division, Oregon no movement, vesicle mediated secretion, organization of endoplasmic reticulum, cytoplasmic streaming
Cellulose
Hemicelluloses- Being hydrogen bonded they limit the extensibility of the cell wall by tethering adjacent microfibrils, aiding in regulating cell enlargement
Pectin- Cements together the walls of contiguous cells. Highly hydrophilic polysaccharides, and the water they attract to the cell wall imparts plastic, or pliable properties to the wall for wall expansion
Callose
Spirally wound chains of glucose residues, oh widely distributed cell wall polysaccharide. Seals plasmodesmata And associate it with the cell plates of dividing cells.
Primary wall layers
Peroxidases, phosphates, cellulases, and pectinases
Fatty substances found in walls (3)
Cutin- found in the walls of epidermis
Suberin- found in the walls of the secondary protective tissue, cork
Both substances combine with wax to reduce water loss
Cellulose synthase
Synthesize cellulose microfibrils in the plasma membrane
Mitosis
A complete set of previously duplicated chromosomes is allocated to each of the two daughter cells nuclei
Cytokinesis
A process that divides the entire cell into two cells
Cell cycle
Watch video
Mitosis and cytokinesis
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