CYTO
study of inherited traits and their variation
genetics
- units of heredity which the transmission of inherited traits
- 35, 000 genes in human genome
genes
- contain the entire "bluepritn" for all human life
- denome bodies found in the nucleus of cell
chromosomes
0n 1842 wing plants
Karl Wilhelm von Nageli
described chromosomes using salamander
walter flemming
arranged from largest to smallest
karyotype
all chromosomes are made from
DNA (deoxyribonucleic acid)
set of observable traits
phenotype
the organism's genetic information
genotype
branch of science stufy of cells, structure
cytology
- lacking of nucleus
- consists of single chromosome
prokaryotic
- contain membrane chromosone
eukaryotic
DNA nucleus give
True cells
- study of chromosomes
- study of normal and abnormal chromosomes
cytogenetics
he use a peaplant (easy to grow) for self folinate
Gregor Mendel
- Father of genetics
- known as Mendelian Inheritance"
Gregor Mendel
" rediscovery of Mendel " by
- basis of the chromosome theory
Hugo de vries
1905 coined the word genetics
William Bateson
- is the functional unit of living organisms
- an organism can be unicellular or multicellular
Cell
the cells of multicellular organisms, such as human, show a great variety of functional and morphological specialization
Evolution
the process by which cells assume specialized structure and function
Differentiation
aka Plasmalemma
plasma membrane
- external lipid membrane
- for transfer of nutrient and metabolites
- attachment of the cell to adjustment cells and extracellular matrix
- communication with external environment
Plasma Membrane
cell layer composed of bilayer of phospholipid molecules that are
amphipathic
- increase by the presence of Unsaturated fatty acids, which prevent close packing on the hydrophobic cell
Fluidity and Flexibility
amphipathic and hhave a kinded conformation- for the prevention of overly dense packing of the phospholipids fatty acid tails
Cholesterol
- largest organelles in the cell
- control center of the cell, cointaining the "blueprint"
Nucleus
heterogenous structures with electron-dense and electronlucent (light)
nuclei
dense areas (tightly-coiled inactive chromatin
heterochromatin
electron-lucent nuclear material that is active in RNA synthesis
euchromatin
heterochromatin and euchromatin are called
chromatin
- sites of ribosomal RNA synthesis and ribosome assemble
- the subunits then passed backed to the cytoplasm to aggregate the complete ribosomes
nucleolus
organelles are suspended in fluid medium called cytosol
cytoplasmic
provide structural support for the cells and its organelles, as well as providing mechanism for transfer of materials within the cell and movement of the cell itself
Cytoskeleton
- made up of many linked monomers of a protein called actin combined in a structure that resembles a double helix
- come togther to form linear, rod-like bundles, but they can also form branching networkss with the assistance of proteins that anchor new side branches
Microfilaments
- a type of cytoskeleton element made of multiple strands of fibrous proteins wound together
- found in many types of animal cells, but typically not in plants or fungi
intermediate filaments
- made up of tubulin proteins arranged to form a hollow, straw like tube, and each tubulin protein consists of two subunits
- like actin filaments, are dynamic structures, and they can grow and shrink quickly the addition or removal of tubulin dimers
- have directionality, meaning that they have two ends that are structurally different from one another.
microtubules
- a stucture found near the nucleus of animal cells, serves as a microtubule-organizing center
- it contains a pair of hollow, rod-like structure that likely perpendicular to each other.
centrosome; centriole
- are long, hair-like structures
- that extent outward from the plasma membrane and are
- used to move an entire cell
flagella
resemble flagella, but are shorter and can generally be divided into two different categories
cilia
- extensive system of flattened membrane bound tubules, saccules, and flattened cisterns
- compartmentalizes the cytoplasm in which increases the surface area for biochemical synthesis
- smooth or rough
endoplasmic reticulum
- plays an important role in the modification of proteins and synthesis of lipids
- it consists of a network of membranous tubules and flattend sacs. The sacs are referred to as cisternae, a general term for membrane structures that come i stacks and have a flattened-pancake structure, and we will see that the golgi also has cistternae
endoplasmic reticulum
it produces lipids, including phospholipids, cholesterol and steroids, and glycolipids (lipids with carbohydrate groups attached)
smooth er
- found near the nucleus and typically forms large, flat sheets
- synthesize new phospholipids for cell membranes
rough er
- scattered free in cytoplasm-relatively large, elongated organelles which have a smooth outer membrane and a convulated inner membrane system
- "powerhouse of the cell"
mitochondria
- dividing cells are needed in order to study chromosomes
- cytogenetics abnormalities result from errors in
cell division
division cells are needed in order to study chromosome
mitosis
division that occurs only on gametic cell
meiosis
- some of the daugther cells progressively specialized and eventually produce the terminally differentiated cells
- most tissues however retain a population of relatively undifferentiated cell population as required
- in the fully developed organism, the terminally differentiated cells of some tissues lose their ability to undergo mitosis
cell division
- cell death
- cell division and differentiation are balanced by cell death both during development and growth of the immature organism and in mature adult
apoptosis
- only human internal organ capable of natural regeneration of lost tissue
liver
- aka CELL DIVISION CYCLE
- series of events that takes place in a cell leading to its division and duplication (replication)
- last about 17-18 hours
- the interval between mitotic divisions or transition of a cell from one interphase through cell division and back to interphase
cell cycle
- longest 9 hours
- chromosomes exist as single chromatids
- cells are metabolically active
- protein synthesis takes place
Gap 1 ( G1)
a cell might be permanently arrested at this stage if it does not undergo further division
G0 Gap Zero
controlled by RNA polymerase
enzyme
- last about 5 hours
- this is when the DNA synthesis occurs
- DNA replicates itself and the chromosome then consist of two identical sister chromatids
synthesis (S phase)
- last about 3 hours
- during this phase, the cell prepares to undergo cell division
- the completion of G2 represents the end of interphase
Gap 2(G 2)
- the final step in the cell cyle
- last only 1-2 hours
- process by which cells reproduce themselves, creatng two daugther cells that are genetically identical to one another and to the original parent cell
mitosis ( M phase)
- chromosomes condense and become visible
- spindle fibers emerge from the centrosomes
- nuclear envelope breaks down
- nucleolus disappears
prophase
- chromosomes continue to condense
- kinetochores appear at the centromeres
- mitotic spindle microtubules attach to kinetochores
- centrosomes move forward opposite poles
prometaphase
- mitotic spindle is fully developed, centrosomes are at opposite poles of the cell
- chromosomes are lined up at the metaphase plate
- each sister chromatid is attached to a spindle fiber originating from opposite poles
metaphase
- cohesion proteins binding the sister chromatids together break down
- sister chromatids (now called chromosomes) are pulled toward opposite poles
- Non-kinetochore spindle fibers lengthen, elongating the cell
anaphase
- chromosomes arrive at opposite poles and begin to decondense
- nuclear envelope material surrounds each set of chromosomes
- the mitotic spindle breaks down
telophase
the genetic material of all cellular organisms and most viruses, the gigantic molecule which is used to encode genetic information for all life on earth
deoxyribonucleic acid (DNA)
within cells, DNA is organized into structures called
chromosomes
normal human cell DNA contained in the nucleus, arranged in
23 pairs of chromosomes
DNA is a long chain polymers of small compound called
nucleotides
each nucleotide is composed of a
base; sugar and phosphate group
the structure of DNA was described by BRITISH SCIENTIST
Watson and Crick
based on chemical and physical data that had been gathered in other laboratories primarily x ray diffraction data by
Rosalind Franklin and Maurice Wilkins
within the structure of DNA, the number of thymine is always equal to the number of adenine and the number of cytosine is always equal to guanine
Chargaff's rules
would produce two copies that each contained one of the original strands and one entirely new strand
semiconservative replication
would leave the two original template DNA strands together in a double helix and would produce a copy composed of two new strands containing all of the new DNA
conservative replication
would produce two copies of the DNA, both containing distinct regions of DNA composed of neither both original strands or both new strands
Dispersive replication
the most dominant form, the base pairs are stacked 0.34 nm apart, with 10bp/turn of the right handed double helix and a diameter of approx, 2nm.
B DNA
form reveals the presense of a major groove and a minor groove. These grooves particularly the minor groove contain may water that interact with amino and keto groups of the bases
B and A DNA
when a DNA solution is heated enough, the noncovalent forces that hold the two strands together weaken and finally break and the two strand come apart
DNA denaturation
the tenperature at which the DNA strands are half denatured. The GC content of a DNA has a significant effect on its
melting temperature
is a reversible process. The two single complementary strands can be made to renaturate or anneal into the native diuble stranded molecule by adjusting the temperature or the salt concentration
denaturation
contains 37 genes, all of which are essential for normal
mitochondrial DNA
thirteen of these genes provides instruction for making enzymes involved in
oxidative phosphorylation
are among the estimated 20,000 to 25,000 total genes in the human genome
mitochondrial genes