ARE YOU
READY?
TONGUE TWISTER
• There with the weather-beaten weatherman.
• Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.
• Three hundred thirty-three thousand three hundred thirty-three.
DISCOVERY OF
NUCLEUS
Oldest known depiction of cells and their nuclei by Antonie van Leeuwenhoek, 1719.
Robert Brown
- introduced the word areola or nucleus, in the cells of the flower's outer layer.
Matthias Schleiden
-name "Cytoblast" (cell builder).
Robert Remak and Rudolf Virchow propagated the new paradigm that cells are generated solely by cells ("Omnis cellula e cellula").
The function of the nucleus clear only later, after mitosis discovered and the Mendelian rules 20th century).
CELL NUCLEUS
CELL NUCLEUS
• Latin nucleus or nuculeus,
meaning kernel.
• The control center of the cell.
• It contains most of the cell's genetic material.
PRIMARY FUNCTIONS:
• Repository of genetic information
• Enables synthesis of nearly all proteins
• Houses the nucleolus
• Responsible for production of ribosomes.
• Selective transportation of regulatory factors and energy.
COMPOSITION
NUCLEAR ENVELOPE
separates the cell's genetic material from surrounding cytoplasm.
serve as a barrier between nucleoplasm and the cytoplasm.
NUCLEOPLASM
made up of water and other dissolved substances. act as a suspension for organelles maintains the shape of the nucleus.
NUCLEAR PORE
composed of multiple proteins allows the passage of molecules
from inappropriate entering or exiting the nucleus.
NUCLEAR LAMINA
• structural support for the nuclear envelope
• anchoring sites for chromosomes and nuclear pores.
PROGERIA
• Defective Lamina protein makes the nucleus unstable. That nuclear instability appears to lead to the process of premature aging in Progeria.
CHROMOSOMES
Multiple linear DNA molecules. During most of the cell cycle these are organized into chromatin During cell division the chromatin can
be seen to form the well-defined chromosomes.
NUCLEOLUS
synthesize rRna and assemble ribosomes.
HAVE
YOU LEARNED?
Which of the following parts of nucleus is responsible for the formation of the ribosomes?
nucleoplasm
nucleolus
nuclear envelope
chromosomes
A
B nucleolus
C
D
In the nucleus of eukaryotic cells, the genetic material is complexed with protein and organized into linear structures called:
centrioles
plasmidshistones
chromosomesA
B
C chromosomes
D
Provide structural support for the nuclear envelope and anchoring sites for chromosomes and nuclear pores.
Nucleoplasm
Cytosol
Nuclear Lamina
Nuclear MembraneB
CA
D
Nuclear Lamina
The space between the membranes is called:
perinuclear space
internuclear space
nuclear space
none of these
A
B
C
D
perinuclear space
It prevents larger molecules, such as nucleic acids and larger proteins, from inappropriately entering or exiting the nucleus.
nuleolus
nuclear envelope
nuclear lamina
nuclear pores
A
B
C
D nuclear pores
It serves as a barrier that prevent macromolecules from diffusing freely between the nucleoplasm and cytoplasm.
nuleolus
nuclear envelope
nuclear lamina
nuclear pores
A
B
C
Dnuclear envelope
ASSIGNMENT:
In 1 whole sheet of paper give a brief description of the following:
• DNA
• Histone
• Centromere
• Telomere