Concept o Cell (Pro, Euc, a multicell life) Flashcards
What are general steps to create protein or DNA and RNA?
- Mixtures of gases can react to form small organic molecules
- Small organic molecules can associate to form polymers
- > amino acids and nucleotides can form polypeptides, in the form of proteins, and polynucleotides, in the form of DNA and RNA
- > A set of 20 amino acids constitute protein
What can polynucleotide guide?
-Polynucleotides have limited capacity as catalysts compared to polypeptides BUT they can guide the formation of exact copies of their own sequence
What determines the phenotype/ genotype of RNA?
- RNA molecule has a specific folded 3D structure which determines the phenotype (gene expression)
- Genotype is determined by the sequence of nucleotides
What was a crucial development for the RNA?
-Development of an outer membrane (enclosing RNA (schließt die RNA ein) was a very crucial development!
Which transition happened 1.5 billion years ago?
-a transition from prokaryotic cells to a larger and more complex eukaryotic cells
What do bacteria often possess?
-Bacteria often possess a protective coat (cell wall), plasma membrane enclosing a single cytoplasmic compartment containing DNA, RNA, proteins and small molecules
How do bacteria replicate?
-Bacteria are small and replicate quickly by binary fission (binäre Spaltungen)
What are the most basic actions of individual organisms to enable survival?
-multipurpose movements:
– Locomotion: to approach or to avoid something
– Orienting: towards or away from something
– Exploring/foraging (aufsuchen) /seeking (includes the first two, plus instigation (anstiftung) by a motivational state)
How do these multipurpose actions take place?
-These take place on a background of maintenance (Wartungs-) activity, including respiration (Atmung), temperature regulation, postural reflexes (Haltungsreflexen)
What do these actions require in multicellular organisms?
-require nervous system control and integration
Describe the general structure of bacteria
- DNA, cell wall, flagellum, ribosomes in cytosol, plasma membrane
- Flagella: are responsible for the motility of the bacteria (moves long axis (Längsachse))
- cell walls: give protection are made of peptidoglycan, which is a polysaccharide chain
- ribosomes: They are the sites where the translation of mRNA takes place, and also they are responsible for the synthesis of proteins
Describe the bacteria morphology
- bacili, cocci, spirilli
- cocci: spherical (kreisförmig)
- bacili: rod-formed (stabförmig)
What is pili? For what is it required
-Pili - slender, hair-like, proteinaceous appendages (Anhänger) on the surface of many (Gram-negative) bacteria
-required for adhesion (Haltung) to host surfaces.
more rigid (starrer) in appearance than flagella
What are capsules? For?
- lies outside the cell wall, thick (up to 10 µm) outer capsule of high-molecular-weight, viscous polysaccharide
- others have more amorphous slime layers
- > Capsules confer resistance to (gegen) phagocytosis
What do eukaryotic cells have (which procaryotes don’t have)?
-have a nucleus enclosed by a double layer membrane
Where is the rest of the content (in eukaryotic cells)?
- The rest of the contents are found in the cytoplasm where many organelles are recognized
- > two most important:
- chloroplasts and mitochondria
What are mitochondria and what is it responsible for?
-is like a bacterium:
contains DNA, is small, makes protein, reproduce by dividing into two
-It is responsible for respiration (Atmung)
What is the name of the eukaryotic cell skeleton? Functions? Composed of?
- internal skeleton/ cytoskeleton which:
- gives the cell its shape, its capacity to move, and its ability to arrange its organelles and transport them from one part of the cell to the other
- is composed of a network of protein filaments: actin filaments and microtubules.
Which role does the nucleus take? Name three regions of the nucleus
-Control center of the cell
-Contains genetic material (DNA)
three regions:
-Nuclear membrane
-Nucleolus
-Chromatin
What is a nuclear membrane? Function? Consists of?
- Barrier of nucleus
- Consists of a double phospholipid membrane
- Contain nuclear pores that allow for exchange of material with the rest of the cell
What are nucleoli? Function?
- Nucleus contains one or more nucleoli
- Sites (standort) of ribosome production
- Ribosomes then migrate to the cytoplasm through nuclear pores
What is chromatin? Composed of? Function?
- Composed of DNA and protein
- Scattered (verstreut) throughout the nucleus
- Chromatin condenses to form chromosomes when the cell divides
What is a plasma membrane? Function? Consists of?
- Barrier for cell contents
- Double phospholipid layer
- Hydrophilic heads
- Hydrophobic tails
- Also contains protein, cholesterol, and glycoproteins
What are the functions of:
Golgi apparatus, Lysosomes, Peroxisome? What do they all have in common?
- Golgi apparatus: modification and transport of the molecules made in the endoplasmic reticulum (ribosomes, lipid synthesis) (red)
- Lysosomes: storage of enzymes required for intracellular digestion (yellow)
- Peroxisomes: generation and degradation of hydrogen peroxide during oxidation (blue, round)
- all these organelles are bounded by a membrane
- > organelles + cytosol = cytoplasm
Which cells are larger Mammalian or plant?
-plant cells are larger approximately 30 x 20 micron
Name the additional organelles which plant cells have?
- central vacuole
- plastids
- cell wall
- specialized adhesion junctions
What is the function of central vacuole? (plant cell)
- tonoplast (Membran) maintains cell’s turgor ( Druck des Zellsafts auf die Zellwand bezeichnet)
- storage (water, ions, and nutrients such as sucrose and amino acids, and waste products)
What are plastids? (Name different plaited + functions)
- organelles found in plants and algae
- chloroplasts for photosynthesis
- Amyloplasts for starch storage
- Chromoplasts for pigment synthesis and storage
- Leucoplasts - can differentiate into more specialized plastids (Amyloplasts - starch storage, Elaioplasts - storing fat, Proteinoplasts - storing and modifying protein)
- (MH - plastids and mitochondria and have own DNA)
What is the cell wall? (plant cell) + Function+ structure
- Rigid (starre) structure outside cell membrane
- No ability to move
- Resist osmotic stresses
- Structure - cellulose, hemicellulose, pectin
What are specialized adhesion junctions?+ function
- plasmodesmata
- cell-cell communication pathways
- allow cell membrane and endoplasmic reticulum of adjacent cells are continuous
What are viruses?
- Not a cell (Latin, virus = toxin or poison)
- Not alive
What do viruses infect?
-Unable to grow or reproduce outside a host cell
-infects living cells
-Infect different hosts (animal, plant and bacterial)
Classified
How are viruses classified?
- RNA or DNA viruses
- double or single stranded
What is a virion?
an entire virus particle (outer a shell)
What is a bacteriophage?
-A virus that infects bacteria
Which genetic material does a virus contain?
-contains DNA or RNA within a protective protein coat (capsid) (Schicht)
What does the cellular transport describe in general?
-There is a continual exchange btw organelles and the outside of the cell
What is endocytosis?
-substances (s.a. Flüssigkeit und Partikel) present in the external medium or molecules previously attached to the cell surface are taken in
What is Exocytosis?
-reverse process of endocytosis
What is phagocytosis?
-unter Phagozytose versteht man die Aufnahme extrazellulärer Partikel, Mikroorganismen oder Flüssigkeiten durch spezialisierte Zellen (Phagozyten)
->it is a form of Endocytosis
(Very large particles or even entire foreign cells can be taken up)
How is multicellular life formed through having single cells?
-Animal cells are bound together by a loose meshwork of large extracellular organic molecules (extracellular matrix) and by adhesions between their plasma membranes (ex: fibroblasts and epithelial cells)
How are epithelial cell sheets formed?
-separate the internal space of the body from the exterior (skin/air interface)
What are the other primitive differentiated (Grundgewebe-arten) cells?
-nerve cells, muscle cells, and connective tissue (Grundgewebe) cells
What do specialized cells set up while interacting and communicating with one another?
- setting up signals (dermis/epidermis)
- >Groups of genes are activated or repressed in response to both internal and external signals
