A&P1 - LP#4 Flashcards
Protein Synthesis & Cell Division
The process which a gene’s DNA is used as a template for synthesis of a specific protein
Gene Expression
There are TWO main steps in Gene Expression
- Transcription
2. Translation
_______________ is when the information encoded in a specific region of DNA is transcribed (copied) to produce a specific molecule of RNA
Transcription
_____________ is when the RNA attaches to a ribosome, where the information contained in RNA is translated into a corresponding sequence of amino acids to form a new protein molecule.
Translation
A sequence of three nucleotides in DNA
Base Triplet
Each base triplet that is transcribed as a complementary sequence of three nucleotides.
Codon
The set of rules that relate the base triplet sequence of DNA to the corresponding codons of RNA and the amino acids they specify
Genetic Code
There are THREE types of RNA made from the DNA template
- Messenger (mRNA)
- Ribosomal (rRNA)
- Transfer (tRNA)
this type of RNA directs the synthesis of protein
mRNA
This type of RNA joins with ribosomal proteins to make ribosomes
rRNA
This type of RNA binds to an amino acid and holds its place on the ribosome until incorporated into a protein. One end of this type of RNA carries a specific amino acid and the opposite end consists of a triplet of nucleotides called an anticodon
tRNA
What is the sequence of Transcription?
Initiation –> Elongation –> Termination
What are the SEVEN steps in the Translation pathway?
- Initiator
- mRNA Complex
- Elongation
- Elongation
- Elongation
- Terminator
- Protein Synthesis Ends
The process by which the cells produce themselves
Cell Division
There are two types of cell division
- Somatic Cell Division
2. Reproductive Cell Division
This type of cell division replaces dead or injured cells and adds new one during tissue growth
Somatic Cell Division
This is the mechanism that produces gametes, the cells needed to form the next generation of sexually reproducing organisms
Reproductive Cell Division
Sex cells (gamete - sperm or oocyte) or precursor cells destined to become a gamete
Germ Cell
Any other cell in the body other than germ cells
Somatic Cells
How many chromosomes do humans have?
46
How many chromosomes are in a sex cell or gamete?
23
2 chromosomes that make a pair
Homologous Chromosomes
Two sets of chromosomes (2n)
Diploid
Cells only having one copy of each chromosome, as in sex sells
Haploid
An orderly sequence of events in which a somatic cell duplicates its contents and divides into two.
Cell Cycle
Two main periods of the cell cycle are:
Interphase - Cells NOT dividing
Mitosis - Cells dividing
DNA replication
High metabolic activity this is where the cell does mots of its growing.
Interphase
What are the THREE phases of Interphase
- G1 Phase
- S Phase
- G2 Phase
During this phase of interphase, replication of organelles and cytosol components occurs (approx 8-10 hours)
G1 Phase
During this phase of interphase, DNA replication occurs (8 hours)
S Phase
During this phase of interphase continuation and maturation of cell growth and preparation for cell division occurs
G2 Phase
During this phase of the cell cycle, the end product is two identical cells
Mitotic Phase
During this phase of cell cycle, division of the cells cytoplasm and organelles occurs. Happens in Late Anaphase. Contractile ring forms cleavage furrow around the centre of the cell.
Cytokinesis
________________ is a normal type of cell death - an orderly genetically programmed death.
Apoptosis
___________ is a pathological type of cell death resulting from cell injury. Cells may swell, burst and spill their cytoplasm
Necrosis
What are the FOUR stages of Mitosis?
- Prophase
- Metaphase
- Anaphase
- Telophase
During this stage of Mitosis chromatin fibres condense into chromosomes consisting of pair chromatids, held together by a centromere. The nucleolus and nuclear envelope disappear and centrosomes move to opposite ends of the cell
Prophase
During this stage of Mitosis centromeres of chromatid pairs line up at the metaphase plate (equator), these are lined up by the microtubules of the mitotic spindle
Metaphase
During this stage of Mitosis centrosomes split, separating the two members of each chromatid pair. Once separated, the chromatids are termed chromosomes. Individual sets of chromosomes move to opposite poles of the cell.
Anaphase
During this state of Mitosis the nuclear envelope and nucleoli reappear. Chromosomes resume chromatin form and the mitotic spindle disappears.
Telophase
This process of reproductive cell division occurs in the gonads (testes and ovaries) and produces a gamete with half the number of chromosomes (haploid)
Meiosis
There are two successive stages of Meiosis
- Meiosis 1
2. Meiosis 2
Meiosis 1 has FOUR phases:
- Prophase 1
- Metaphase 1
- Anaphase 1
- Telophase 1
During this phase of Meiosis 1 chromosomes shorten and thicken. Nuclear envelope and nucleoli disappears and mitotic spindles form
Prophase 1
During this phase of Meiosis 1 tetrads line up along the metaphase plate of the cell and homologous chromosomes are side by side.
Metaphase 1
During this phase of Meiosis 1 each homologous pair of chromosomes separate as they are pulled to opposite poles of the cells by microtubules
Anaphase 1
During this phase of Meiosis (similar to mitosis) nuclear envelopes and nucleoli reappear. Chromosomes resume chromatin form and mitotis spindles disappear. The cytoplasm replicates
Telophase 1 & Cytokinesis
________________ begins with a diploid starting cell and ends with two cells that are haploid
Meiosis 1
________________ begins with each of the 2 haploid cells from Meiosis 1 and they divide to get a net result of 4 haploid cells (gametes)
Meiosis 2
