Fragenkatalog

→ Diameter: 7,7µm Thickness: 2µm

An assumption which validity has not been proven but is suitable for explaining a phenomena

When you stay up late you’ll be tired the next day

Explanation of aspect of the natural world → Has to be tested and confirmed

Einstein relativity Theory

Simplified representation of reality

Bohr model of an atom

Light microscope, Scanning electron microscope, Biocular Magnifier

Proteinaceous infectious particles (Have no DNA or RNA). Can cause disease in Human (Creutzfeldt Jakob) and animals (BSE)

Size: V: -50nm B- 10µm

Replication: V: Needs host B: binary fission

Cellwall: V: Protein coat B: Peptidoglycan

Female Egg cell (250-300µm)

Smallest functional unit of an organism

Golgi apperatus, Nucleus, Ribosomes, Endoplasmatic reticulum,Mitochondria, Lysosome

• Euchromatin: Active areas- A loosely coiled

• Heterochromatin: Inactive areas - DNA tightly coiled (histones)

Active cells have a large amount of euchromatin

It is the genetic controllcenter and contains genetic information in form of DNA

Regulation of export of mRNA from nucleus to cytoplasm

→ It is a dense, fibrillary compound directly under the nuclear envelope

→ Nuclear stability, organisation of chromatin, binding nuclear pore complexes

→ Protein biosynthesis + folding

→ Membrane production (Integral membrane protein, luminal proteins)

It is needed for synthesis of various lipids and steroids, plays important role in detoxification of the cell

→ Two subunits

• Small subunit (40s)

• Large subunit (60s)

  20-30 nm

→ Oxidativ phosphorylation → Generates ATP

Theory of the origin of eukaryotic cells from prokarytic organisms → Example: Mitochondria (Has two cell membrane layers)

Mitochondria have their own DNA

→ They have two membranes

→ Hydrogen, Carbon, Oxygen, Nitrogen

→ Protons + Neutrons

Its the tendency for an atom to attract shared electrons

It describes the probability of residence of the elctrons

→ Strong Bindings:

• Covalent bindings

• Ionic bindings

• Metal binding

→ Weak Bindings:

• H- bringe bindings

• Van der Waals forces

Adenosine, Thymine, Gunanine, Cytosine

Adeonosine - Thymine, Cytosine- Guanine

Nucleobase + sugar molecule

Nucleobase + sugar molcule + phosphate

Making a copy of a DNA / Nucleus

Copying a segment of DNA into RNA

Ribosomes in the cytoplasm synthesize proteins of the information on the RNA

Centromere links a pair of sister chromatids together during cell division

Region of repetitive nucleotide sequences at the end of chromosomes

→ 23 Paris of chromosomes, 46 chromosomes in total

DNA molecules + histones

→ Proteins that provide structual support for the DNA → DNA wraps around histones

→ 5’ to 3’ direction

→ Short sequences of DNA nucleotides which are synthesized discontinously and later are linked together

It explains why multiple condons can code for a single amino acid

→ Introns are non coding sections ind DNA and RNA

→ Exons are coding sections in DNA and RNA

→ Saturated: fatty acid chains have all single bonds → Can cause fatty deposits in blood vess.

→ Unsaturated: fatty acid chains contain one or more double bonds

→ 3 fatty acids + glycerol

• Protein biosynthesis: Translation of mRNA takes place at the ribosomes → Basis for production of proteins

• The ribosome reads the mRNA and connects amino acids with another.

Membrane enclosed cavities also called cisterns. 4-6 dictyosomes form the golgi apparatus

The Golgi apparatus, or Golgi complex, functions as a factory in which proteins received from the ER are further processed and sorted for transport to their eventual destinations: lysosomes, the plasma membrane

If cell division occurs in the cell, the Golgi apparatus disintegrates and is divided into both daughter cells, where it then reassembles.

They are formed in the Golgi aparatus

lipases, proteases and nucleases within the lysosome are able to break down foreign and cell specific material

Around pH 4.5-5

Lysosomes are embedded in cytosol (pH 7.2)

Depending on cell type

Plant: They can serve as storage (Waste products, toxins) and create proteins

1. Prophase

2. Metaphase → Prometaphase

3. Anaphase

4. Telophase

5. Interphase

1. Prophase: Condensation of chromosomes

2. Metaphase: Spindle fibers attach to centromers and align them to the equator of the cell Prometaphase: Degradation of the nuclear envelope

3. Anaphase: Separation of chromatids

4. Telophase: Despiralization of chromosomes, reconstruction of the nuclear envelope → eventually telokinesis (Cell division)

5. Interphase: During this phase the cell grows and replicates its DNA

Cells with double set of chromosomes diploid become daughter cells with a single set of chromosomes (haploid)

First gamates go into meisois 1 and then into meiosis 2. Meaning, that there are two cell divisions leading to 4 daughter cells

• Meiosis 1: Chromosome set is halved, from 46 Chromosomes to 23 Chromosomes

• Meiosis 2: Chromosomes are divided into two chromatids

• Prophase

  • Letotän - Condensation of chromosome

  • Zygotän - Mating of homologous chromosomes

  • Pachytän - Subdivision into two chromatids

  • Diplotän - Parralell arrangement loosens Crossroads visible as chiasmata

  • Diakinese - Maximum condensation of Chromosomes, Dissolution of nuclear membrane

• Metaphase 1

• Anaphase 1

• Telophase 1

Further cell and nuclear division → Chromosomes are divided into two chromatids

• Recombination in meiosis: new mixture, new properties

• Sexual reproduction: variability

• Variability and selection as basis of evolution of new species

• Phospholipids: 2 fatty acids with glycerol nd phosphoric acid → Polarity

Membrane proteins: Transporter and Channeks

• Active transport by transporter + ATP

• Ionchannels

Yes, within the PNS damaged nerve cells can grow back (Proteins)

No, within the ZNS damaged nerve cells cannot regenerate

• Sceletal muscle can regenerate in response to an injury

• Cardiac muscle is unable to regenerate → replacement with a scar

• Smooth muscle cells can regenerate

• undifferentiated cells

• Earliest type of cell in the cell lineage

• Cells from which all the other cells are speciacialised

• Adult bone marrow cells

• Umbilical cord blood

• Growth factor mobilized peripheral blood

• Are found in the human blastocyst prior to implantation

• Are Pluripotetnt → Can proliferate and differentiate into all three embryonic germ layers

• When extracted the embryo gets destroyed

• Immunorejection: It is still a problem, although MSCs and placental tissue as well as iPSCs circumvent the problem.

• The genetic stability of stem cells remain to be elucidated. Genetic instability may give rise to tumor formation.

• Mesoderm

• Ectoderm

• Endoderm

The death of individual cells in a living organism that have not been “Instructed” to die.

• Oxygen or nutrient deficiency due to: Injuries, toxins, frostbite, burns

Mesoderm: Skelett, Muskeln, Gefäße

Ectoderm: CNS, PNS, Epidermis

Endoderm: Darm, Lunge, Leber

• Pyknosis

• Karyolysis

• Karyorrhexis

Most common form of necrosis

Cell swelling with eosinophilia, denaturation of cytoplasmic proteins and decomposition of organells

typicall after Hypoxia → occurs in all tissues except brain

A condition in which the blood flow to a large are is cut off. The tissue then breaks down and dies leading to greenish black colour.

• Dry gangrene: Evaporation of liquid leads to mummification and drying of the tissue e.g. diabetic foot

• Moist gangrene: caused by infection with putrefactive bacteria

Apoptosis is controlled suicide of cells compared to necrosis, apoptosis does not lead to release of plasma and does not trigger inflammation. It is on purpose and and programmed.

• around half of originally formed nerve cells die before birth

• Ensurance of correct interconnection of brain structures and nerve cells

• by apoptotic cell death the light transmission of the lens in the eye is achieved

• Frog: metamorphosis frpm tadpole to frog

• To controll cell count and size of tissues

• elimination of degenerated cells

• Ensurance of plasstcity in the central nervous system

• degredation of potentially harmful cells

Loss of apoptosis controll allows cancer cells to survive longer and accumulate mutations.

In cancer reasearch one goal is to trigger controlled cell death in abnormal cells

• Hyperthrophy

• Hyperplasie

• Athrophy

• Metaplasia

Increase of size of cells → Muscular hypertrophy in response to exercise

Increase in number of cells → Increase of thickness of endometrium during mestrual cycle

Cell reduction → shrinkage of thymus in early childhood years

Conversion of one cell type to another → Conversion of fibrous tissue into bone

• Gap junction

• Adherens junction

• Desmosomes

• Tight junction

It anchors intermediate filaments tn a cell to the extracellular matrix

Connects intermediate filaments in one cell to those of another cell

Connects actin filament bundle in one cell with that in the next cell

→ Seals gap between epithelial cells

→ They are important cell adhesion molecules forming adherens junctions

→ It allows the passage of small water soluble molecules from cell to cell

→ Connects two cells

→ Molecules with a molecular weight of less dann 1000 dalton can pass, larger ones are restricted

→ Couples cells electrically and metabolically

It is a specialized form of extracellular matrix also known as the basement membrane

• Provides support to overlaying epithelium

• 4E staining

• Azane dyeing

• Van gieson dyeing

• 4% Formaldehyde solution

• Zenkers mixture

• Bouin solution

• Simple squamous

• simple cuboidal

• Simple columnar

• stratified squamous

• stratified cuboidal

• Stratified Columnar

It consists of a large number of cavities enclosed by membranes and runs through the entire cell, it is also occupied by ribosomes

During mitosis the nuclear evelope dissolves for the time of the division

Alkaloids e.g. cholchicin

they are responsible for transport along microtubules dynein moves torwards the negative end and kinesin moves torwards the positive end of the microtubules

These are a structure of microtubules inside eukaryotic cilia

Nine peripheral double microtubules sorround two single centralmicrotubules in the middle. Axoneme are found in kinocilia and sperm flagella

under optimal conditions it takes about 20 min.

Cell division is the biological process of dividing a cell

It is divided into nuclear cell division (mitosis) and plasma division (cytokinesis)