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Apologia Biology Module 7 :Mitosis, Meiosis, Translation, Transcription

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Mitotis vs. Meiosis Meiosis v. Mitosis animation and details

Vocabulary and review questions:

Events during Mitosis

Interphase: Cells may appear inactive during this stage, but they are quite the opposite. This is the longest period of the complete cell cycle during which DNA replicates, the centrioles divide, and proteins are actively produced. For a complete description of the events during Interphase, read about the Cell Cycle.

Prophase: During this first mitotic stage, the nucleolus fades and chromatin (replicated DNA and associated proteins) condenses into chromosomes. Each replicated chromosome comprises two chromatids, both with the same genetic information. Microtubules of the cytoskeleton, responsible for cell shape, motility and attachment to other cells during interphase, disassemble. And the building blocks of these microtubules are used to grow the mitotic spindle from the region of the centrosomes.

Prometaphase: In this stage the nuclear envelope breaks down so there is no longer a recognizable nucleus. Some mitotic spindle fibers elongate from the centrosomes and attach to kinetochores, protein bundles at the centromere region on the chromosomes where sister chromatids are joined. Other spindle fibers elongate but instead of attaching to chromosomes, overlap each other at the cell center.

Metaphase: Tension applied by the spindle fibers aligns all chromosomes in one plane at the center of the cell.

Anaphase: Spindle fibers shorten, the kinetochores separate, and the chromatids (daughter chromosomes) are pulled apart and begin moving to the cell poles.

Telophase: The daughter chromosomes arrive at the poles and the spindle fibers that have pulled them apart disappear.

Cytokinesis: The spindle fibers not attached to chromosomes begin breaking down until only that portion of overlap is left. It is in this region that a contractile ring cleaves the cell into two daughter cells. Microtubules then reorganize into a new cytoskeleton for the return to interphase. source:



Process whereby DNA encodes for the production of amino acids and proteins.

This process can be divided into two parts:

1. Transcription
Before the synthesis of a protein begins, the corresponding RNA molecule is produced by RNA transcription. One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize a messenger RNA (mRNA). This mRNA migrates from the nucleus to the cytoplasm. During this step, mRNA goes through different types of maturation including one called splicing when the non-coding sequences are eliminated. The coding mRNA sequence can be described as a unit of three nucleotides called a codon.

2. Translation
The ribosome binds to the mRNA at the start codon (AUG) that is recognized only by the initiator tRNA. The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes, composed of an amino acid linked to tRNA, sequentially bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into polypeptidic sequences dictated by DNA and represented by mRNA. At the end, a release factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.

One specific amino acid can correspond to more than one codon. The genetic code is said to be degenerate.  Source :




Tips/ and elementary breakdown 🙂

Make sure to read and understand page 199 (Transcription).  KNow the nucleotide bases that link up to DNA.

Transciption is similar to a copy and translation is -changing the language of the nucleotide base sequences in RNA to the langueate of amino acid sequences in a protien

Diploid  number = haploid x 2

Haploid number  = dipoid /2

Diploid has two , Haploid has one

Lytic pathway- the way a virus comes in to destroy a cell and take over- since virus’ can’t multiply themselves, they have to infect or destroy a cell and new virus’ are released to infect other cells.

Antibody-  a protein the helps kill the virus (bad germ!) Once they fight the virus, the cells remember how this enemy came in to attack them so the next time this germ comes by again, it can’t get in like it did last time.

Vaccine- a shot- or a weak version of the virus so the cells know how to fight the virus if it ever comes around poking around to infect you.


Author: Ancient Paths

“But blessed is the one who trusts in the LORD, whose confidence is in him. They will be like a tree planted by the water that sends out its roots by the stream. It does not fear when heat comes; its leaves are always green. It has no worries in a year of drought and never fails to bear fruit.”

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