Test 19/9 Cell Biology Flashcards
Info about cells, movments + functions
Mycoplasma = smallest cell
Different movements = amoeboid, ciliary, flagella etc
Functions = Ability to respond to changes, grow and develop, reproduce, have metabolism, maintain homeostatis
How do cells work?
Cell membrane separates the inside of the cell from the outside
Genetic material pass traits to the cells offspring
Reproduce thru cells DNA, creates metabolic and reproductive functions
What can the cells functions be
Include photosynthesis
locomotion
copying its own DNA
Let certain substances pass thru the cell membrane
What is protein made of
Amino acids
Comes in diffrent sizes, shapes and properties - polarity, ion charge and hydrophobicity
What functions can amino acids do
When they are out toughter - the cells can do almost any function
What gives the Prokaryotic cells shape
The cell wall in bacteria
algae
fungi
plant cells
What gives the Eukaryotic cells shape?
The shape of the cell depends on its function
Do Prokaryotic cells have nucleus?
No, insteed they have single chromosome
What are Prokaryotic cells
Unicellular organisms
Lack organelles or internal membrane bound structures
Circular, doubel stranded DNA
Have cell wall outside the plasma membrane
Nucleoid, meaning
60% DNA, small amount of RNA + proteins
Have the Prokaryotic cells genetic material
Transkription + replication of DNA takes place
Plasmids, meaning
Carries genetic information
Capeble of replication, can transfer from cell- to cell
Extrachromosomal
Double teamed, circular DNA molecules
Replicate independiataly
Transmissible plasmid
Transfer from cell to cell by conjugation
Nontransmissible plasmid
Do not contain the transfer gene
Eukaryotic cells
Complex cells, single cell
Genetic information- chromosomes in the cells nucleus
Cell membrane nucleus
(Animal, protist & fungal cell)
Nucleus
Double membrane
Nucleoplasm
Chromatin
Nucleus
Stores DNA
Cordinates cells activity
Cell division
Endoplasmic reticulum
Forms interconnected network of membrane enclosed sacs (cisternea)
Endoplasmic rough
Manufacture proteins, enzymes, transport protein to the Golgi apparatus
Endoplasmic smooth
Synthesis of lipids, phospholipids, steriods
Golgi apparatus
Modify, package the macromolecules that synthesised by the cells for secretion purpose in the cell
Mitochondria
Generation of metabolic energy in Eukaryotic cells
Cytoskeleton
Interlinking filaments, tubules thru the cytoplasm from the nucleus to the plasma membrane
Chromosomes
Thread like structures in which DNA is packaged within the nucleus. DNA is collided around histones (structure support) And help during cell division
Each have a centeromere
Have an:
Nucleus, centromere, chromatin, nucleosomes, histones, basse pairs, double stranded DNA
Telomere
Critical role of preserving the genomic sequence
Eukaryotic cells three components
Cell membrane
Cytoplasma (around the nucleus)
Membrane limited nucleus contain DNA
Membrane limited nucleus
Carries the genetic code for protein synthesis and for cell activites. Determine parts of the genetic code for delivering info til the cytoplasm
Lipids in cell membrane
Include:
phospholipids
sphingolipids
Cholesterole
Membrane phospholipids
Arranged in bilayers, tails directed toward one another at the center of the membrane
Two groupes of protein
- Integral protein = folded with hydrophilic amino acids, in contact with the membrane phospholipids
- Transmembrane proteins = penetrate the entire membrane and protrude from both sides
Pernipheral membrane proteins
Associated with inner or outer membrane surface and are realesed in salt solutions
Membrane assymetry
Differensens in chemical compositions between the bilayers inner or outer halves
Integral proteins
May diffuse to and accumulate in one membrane region
Oligosaccharies
Occur only on the plasma membrames outer surface
Phospholipid
Occure on the outer half
Has more p+s (inner half)
Has more p+p (outer half)
Membrane four functions
- Selective permeability = function of steady state, homeostasis, required for cell survival
- Signal transduction = integral membrane receptor proteins with strong bindning affinites for signal molecules. Found in cell surface
- Endocytosis = cells engulf extracellular substances and bring cytoplasm in membrane limitade vesicles by this mechanism
- Exocytosis = ejects substances from the cell. Use this both for secretion and for exretion of undigested material
Homeostasis
Attribute to cell membrane maintain optional intracellular concentrations of water, ions and enzymes
Selective permability stages
- Passive diffusion = some water/lipids can cross the membrane in both directions (wihtout cell expending energy)
- Facilitated diffusion = some molecules are helped across the membrane by membrane component. Unidirectional, no energy
- Active transport = Exit or enter a cell against a gradient. Need energy. (ATP) concentrasion is higher outside.
Signal transduction stages
- Ligand-gated
- Enzyme linked receptors
- G-protein couple receptors
- Steroid hormone
Endocytosis stages
- Phagocysts (cell eating) = can eat entire bacteria or macromolecules
- Pinocytosis (cell drinking) = can drink small amounts of fluid
- Receptor mediated endocysts = binding of ligand to receptor that makes a Clarthrin coat s31
Types of cell transport
Compartmentalization
Spatinal temporal organisation of metabolic process
Storage, transport and secretion
Cytoplasm
Is in all material within a cell, enclosed by cell membrane
Main components:
Cytosol
Organells
Cells internal sub structure
Cytoplasmic inclusions
Cytosol
Component of the cytoplasm
Cell membrane
Organells
In prokaryotic cells, the cytoplasm and Cytosol are the same
Dont have! Mitochondria, choroplast, vacuoled
Parts of the cytoskeletal filaments
Actin filaments = globular protein, component of the muskel cell
Microtubules = play a role in cell structure, mitosis o movment
Intermediate filaments = strukturalistisk protein in Eukaryotic cells
Historical overview of cell biology
Basic Unit of life
Cell biology encompasses both Prokaryotic and Eukaryotic cells
Can be dividend in many sub-topics
Theory of cell
All know living things are made up by cells
Structural o funktional Unit of all living things
All cells come from per-existens cells by division
Cell communication
Composed by different types of cells
Communicate by physiological signals among cells
Synaps
An small gap/junction between two neurons and a tissue cell
Signal molecules
Most are water soluble, too large to pass thru the plasma membrane.
It can only bind to one signal molecule at a time
Receptors for chemical messengers are proteins
Three signal pathways
- Receptor = Of extra signal cell. Chemical signals form paracrine, outocrine and hormoner that released from cells inte extracellular components. The signal recognize the torget cell sur to specific receptors.
Occurs at a specific region = binding site.
Ligands = binds to first Messenger -> produces an effect-> agonist or atagonsit. - Intracellular signal transduction = Of signal outside of cell to inside of cell. Receptors for lipid soluble hormoner located in Cytosol or nucleus
Membrane receptors
G-protein - Cellular response = is initiated or occurs within the reciving cell
G-protein
Important during embryonic development and sensory system
Cellular response
More than one response can result from the reseptor of a singel ligand
Physological signals
Electrical signals = changes in a cells membrane potential
Chemical signals = moleucles secreted inte the extracellular fluid by the cells. Responseble for most communication between cells
Traget cells = recive electical or chemical signals
Chemical signals = distributes by diffusion, reach target cells by diffusing by interstinal fluid.
Autocrine
A singel molecule acts on the cell secreting it
Paracrine
Chemical that is secreted by a cell to act on cells immidiate vicinity
Cell to cell comuntication
Direct cytoplasmic transfer
Local communication
Long distansen communication
Direct cytoplasmic transfer
Of electrical signals thru gap junction that connect adjacent cells
Local communication
Chemicals diffuse thru the extracellular fluid
Long distance communication
Combination of electrical signals carried by nerve cells and chemical signals transporter in the blod
Membrane - Resting potential
Cells of the body have an electrical charge that can be measured across thier other cell membrane
Action membrane potential
When the membrane potential of a nerve or muscle is reduced sufficiently a fhurter and drastic change in the membrane potential
Ion channels
Sodium = Na+
Potassium = K+
Chloride = CI-
