Chapter 4 Flashcards
Magnification
The ratio of an objects image size to its real size
Resolution
The measure of the clarity of the image; it’s the minimum distance two points can be distinguished.
Contrast
The difference in brightness between the light and dark areas of an image
Organelles
Membrane bound structures within eukaryotic cells
Electron microscope
Focusses a beam of electrons through the specimen or onto its surface. Electron microscopes Can see bacteria, proteins, lipids, and organelles
Describe the following
- unstained specimen
- phase contrast
- fluorescence
- confocal
Little contrast
Enhances contrast but kills specimen
Labels molecules with fluorescent dyes which absorb ultra violet light
Sections the fluorescent molecules to create 3D view
Plasma membrane
The membrane at the boundary of every cell that acts as a selective barrier, regulating the cells chemical composition.
What does the plasma membrane have in or on it?
Enzymes in them, embedded are lipids and proteins
Describe some key features of the nucleus
- contains most of the genes in Eu. Cells
- most noticeable structure
- has nuclear envelope with nuclear pores
- nuclear lamina: netlike array of protein filaments that maintains shape of the nucleus by supporting the envelope
- chromosomes are wrapped in proteins to coil them and reduce length. (Chromatin)
Nucleolus
A specialized structure in the nucleus consisting of chromosomal regions containing ribosomal RNA genes along with ribosomal proteins imported from the cytoplasm; site of RNA synthesis and ribosomal subunit assembly.
Ribosomes
Are they membrane bound?
A complex of rRNA and protein molecules that functions as a site of protein synthesis Im the cytoplasms: consists of a large and small subunit. In euk. Cells subunit is assembles int he nucleolus.
Not bound= not organelles
What are the two types of ribosomes
Free- suspended in cystol( proteins made are made for cystol)
Bound- attached outside of rough ER or nuclear envelope. Make proteins to be in membranes within certain organelles. Exm. Lysosomes
Endomembrane system and its consisting parts
Regulates protein traffic and performs metabolic functions. Includes plasma membrane, nuclear envelope, smooth and rough ER, Golgi apparatus, lysosomes, vesicles and vacuoles.
It synthesizes proteins, transports proteins into membrane or organelles in or out of cell, metabolism, movement of lipids and detoxification of poisons.
What are all the parts of the endomembrane system connected by!
Vesicles: a membranous sac I’m the cytoplasm of Euk. Cells.
What is the endoplasmic reticulum?
An extensive membranous network in Euk. Cells continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome free (smooth) regions.
What is the smooth ER responsible for?
Functions may include synthesis of lipids, metabolism of carbs, detoxification of drugs and poisons (addition of hydroxyl group),and calcium ion storage. Enzyme here. Synthesis lipids;oils, steroids, new membrane phospholipids.
What is the rough ER responsible for?
Produces proteins that cells secrete
Glycoproteins- proteins with carbohydrates covalently bonded
Transfer proteins with transport vesicles
Membrane factory for cells; grows in place by adding membrane proteins and phospholipids to self. Makes hydrologic enzymes
What is the function of the Golgi apparatus?
(Shipping and receiving)
Products of ER are modified, stored and sent out.
Manufacturing some macromolecules (polysaccharides)
What makes up the Golgi and what do they have?
Cisternas layers that have inferential enzymes for different functions.
Lysosomes
Where do enzymes here work best?
A membranous-enclosed sac of hydrologic enzymes found in the cytoplasm of animal cells and some plants that are used to digest (hydrolyze) macromolecules.
=inside the acidic environment of lysosomes.
Phagocytosis vs. Autophagy
Eating/ingesting
Phagocytosis vs autophagy?
Phagocytosis is when a foreign substance is engulfed by the cell.
Autophagy occurs when a lysosomes is fused with autophagosomes in order to digest the dysfunctional structures. (Recycle)
What is the function of transitional endoplasmic reticulum?
(Site of transportation)
Exit site for proteins leaving granular endoplasmic reticulum (rough) destined to enter Golgi
Vacuoles
What are the types
Large vesicles derived from the endoplasmic reticulum and Golgi apparatus. Part of membrane system.
Food vacuoles- formed by phagocytosis
Contractile vacuole- move excess water out of the cell.
Central vacuole
Central vacuole
In a mature plant cell a large membranous sac with diverse role in growth, storage, and removal of toxic substances.
When central vacuole becomes bigger so ones the overall plant cell.
Describe the endomembrane system in detail
- nuclear envelope is connected to rough ER, which is continuous with smooth ER.
- Membranes and proteins produced from ER flow in transport vesicles o the Golgi.
- Golgi pinches off transport vesicles and other vesicles that give rise to lysosomes.
- lysosomes available for fusion with vesicles of digestion.
- transport vesicles carries proteins to the plasma membrane for secretion.
- plasma membrane expands by fusion of vesicles.
Mitochondrion
An organelle in euk. Cells that served as the site of cellular respiration; uses oxygen to break down organic molecules and make ATP.
Chloroplast
Organelle in plants and photosynthetic protists that absorb sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.
What is the endosymbiont theory
Early ancestor of euk. Cells engulfed an oxygen using, non photosynthetic prok. Cell eventually row engulfed cell became enclosed inside. (Cell living in cell). They merged into single organism; euk. Cell with mitochondrion. Eventually it ate a photosynthetic prok. Resulting in a photosynthetic eukaryotes.
How many membranes do mitochondrion have
Two with phospholipid bilayers. Outer membrane is smooth, inner is convoluted with filings called Christae.
What do te double membranes of mitochondrion separate?
Inter-membrane space: between inner and outer membrane
Mitochondrial matrix- contains different enzymes as well as mitochondrial DNA and ribosomes.
What separates the chloroplast from the cytoplasm
An envelope made of two membranes separated by inter-membrane space.
What are thylakoids?
Flattened membranous sac in chloroplasts, that exist in stacks called grana that are all interconnected. Thylakoids convert light. Energy to chemical energy.
What is the stroma
Fluid outside the thylakoids which consist of chloroplast DNA ad ribosomes and enzymes.
Peroxisomes
An organelle containing enzymes that transfer hydrogen atoms from various substance to oxygen, producing and then degrading hydrogen peroxide.
Digest alcohol
Hurt bacteria
Cytoskeleton
Network of fibres extending through the cytoplasm. It organize activities and holds structures of the cell.
Motor proteins
A protein that interacts with cytoskeleton elements and other cell components, producing movement of the whole cell of parts of cell.
Feet like movement
What are the three types of fibres that make up the cytoskeleton?
Microtubules
Microfilaments
Intermediate filaments
Describe key features of micro tubules
- tracks for motor protein containing organelles.
- centrosomes +centrioles
Micro tubules grow out of Centrosome and aid in cell division
-make up flagella and Cilia
Key feature of microfilaments
- cause muscle contractions
- microvilli; increase surface area for absorption
- form network under cell membrane that hold cell shape
- move and push cell along
Key features of intermediate filaments
- nucleus sits in cage of intermediate filaments (nuclear lamina )
- constructed of proteins whose members include keratin in hair and nails
- permanent fixtures of cells
Cell wall
Protective layer external to plasma membrane in the cells of plants. Walls are made up of cellulose in plants, peptidoglycan in bacteria, and chitin in fungi.
Cilia vs. Flagella movement
Cilia- move back and forth
Flagella- rotational, propeller motion
What makes up the extracellular matrix of animal cells?
Glycoproteins and other carbohydrate- containing molecules secreted by the cells. Most abundant glycoprotein is collagen which forms strong fibres outside the cell.
Proteoglycans
A protein with 1 or more covalently bonded carbohydrates.
In ECM
Fibronectin
An extracellular glycoprotein secrete by animal cells that helps them attach to thee extracellular matrix.
Integrins
In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton.
This transmits signals from ECM to cytoskeleton
Cell junctions
Neighbouring cells in an animal or plant cell often adhere and interact via sites of direct contact
Plasmodesmate
In plant cells is an open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, ad larger molecules to pass between.
What are the three types of cell junctions in animal cells?
Tight junction- prevents leakage of material
Desmosomes- acts as rivet, fastening cells together
Gap junctions- allows passage of materials between cells
Transitional ER
Site of formation of transport vesicles
Movement of products to organelles
Secretion of products from cell
Where are polysaccharides made
Golgi apparatus
