Cell Division Flashcards
a series of changes the cell experiences from the time it is formed until it divides
the period between the beginning of one cell division and the beginning of the next cell division
Cell Division
Cell life cycle has 2 major periods
Interphase
Cell division
Metabolic phase
Cell grows and carries on metabolic processes
Longest phase of the cell cycle
Interphase
Cell reproduces itself
Cell division
Genetic material is duplicated and readies a cell for division into two cells
Occurs toward the end of interphase
Process of DNA replication
CELL DIVISION
Body Cell Division
It involves
Somatic Cell Division
3 major processes of Somatic Cell Division:
i, m, c
interphase, mitosis, and cytokinesis
- Is a very active period of cell activity during which DNA in the nucleus doubles
- The phenomenon is called “Replication”, meaning that DNA makes the copy of itself.
Interphase
• division of the cytoplasm into two distinct daughter cells
Cytokinesis
- Is the process during which two diploid (2n) daughter cells result from the division of a diploid (2n) parent cell
- 4 sequential stages: prophase, metaphase, anaphase, telophase
Mitosis
division of the nucleus
Results in the formation of two daughter nuclei
MITOSIS
division of the cytoplasm
Product: Two daughter cells exist
Begins during late anaphase and completes during telophase
Cytokinesis
EVENTS OF MITOSIS:
PMAT
Prophase, Metaphase, Anaphase, Telophase
Chromatin coils into chromosomes
chromatids are held together by a centromere
Centrioles direct the assembly of a mitotic spindle
Nuclear envelope and nucleoli have broken down
Prophase
- Chromatin condenses and shortens into chromosomes.
* Each prophase chromosome has chromatids
Early Prophase
• Each prophase chromosome has a pair of identical, double- stranded DNAs called
CHROMATIDS
- Disappearance of the NUCLEOLI.
- Breakdown of the NUCLEAR MEMBRANE.
- Movement of the two CENTRIOLES toward opposite directions.
- Appearance of MITOTIC APPARATUS
Late Prophase
Line up in the middle
Chromosomes are aligned in the center of the cell on the metaphase plate
Center of the spindle midway between the centrioles
Straight line of chromosomes is now seen
the CHROMATID pairs line up at the center of mitotic apparatus
Metaphase
Pulled away
Centromere splits
Chromatids move slowly apart and toward the opposite ends of the cell
the phase is over when the chromosomes stop moving
Movement of the two sister chromatids of each chromosomes toward opposite pole of the cell
Anaphase
Reverse of prophase
Chromosomes uncoil to become chromatin
Spindles break down and disappear
Nuclear envelope re-forms around chromatin
Nucleoli appear in each of the daughter nuclei
Formation of nuclear membrane around each set of chromatin.
Appearance of nucleoli.
Mitotic apparatus disappears.
Telophase
in telophase, Formation of two daughter cells with __chromosomes each.
46
In most cases, M and C occur together
Mitosis Cytokinesis
In some cases, the c is not divided
cytoplasm
serves as a blueprint for making proteins
DNA
DNA segment that carries a blueprint for building one protein or polypeptide chain
Gene
Where to find ribosomes?
Rough ER
protein that the building materials for cells
structural
Fibrous proteins
protein that act as enzymes (biological catalysts)
functional
Globular proteins
Most ribosomes, the manufacturing sites of proteins, are located in the
cytoplasm
DNA never leaves the nucleus in ___cells
interphase
DNA requires a ___ and a ___ to carry instructions to build proteins to ribosomes
decoder messenger
Both the decoder and messenger functions are carried out by
RNA
single-stranded
contains ribose sugar instead of deoxyribose
RNA
3 varieties of RNA
tRNA
rRNA
mRNA
Transfers appropriate amino acids to the ribosome for building the protein
Transfer RNA (tRNA)
Helps form the ribosomes where proteins are built
Ribosomal RNA (rRNA)
Carries the instructions for building a protein from the nucleus to the ribosome
Messenger RNA (mRNA)
2 major phases of protein synthesis
Transcription
Translation
happens in nucleus
Transcription
happens in cytoplasm
Translation
Transfer of information from DNA’s base sequence to the complementary base sequence of mRNA
Each DNA triplet corresponds to an mRNA codon
Transcription
in Transcription DNA is the template for ___; mRNA is the ___
transcription - product
Base sequence of nucleic acid is translated to an amino acid sequence; amino acids are the building blocks of proteins
Occurs in the cytoplasm and involves three major varieties of RNA
Translation
