Sign Up Now
Get instant access to over 1 million+ study documents
OR
Already registered? click here to login
By creating your account, you agree to our terms of service, privacy policy and student honor code.
Mitosis vs. Meiosis
Mitosis and meiosis are both processes of cell reproduction.
Mitosis is the process by which eukaryotes reproduce asexually and also how multi-celled eukaryotes reproduce cells for bodily growth. Meiosis is the process by which eukaryotes sexually reproduce. Using humans as the examples, new humans are created by meiosis, but within the human, mitosis reproduces cells. Mitosis results in two identical cells, that is the two cells are clones of each other. Meiosis results in four cells that are not identical, the process of meiosis shuffles the genetic information. By describing the two processes, we will see how this occurs.
Mitosis
In mitosis first the chromosome duplicates, creating two sister chromatids, these sister chromatids are identical. The sister chromatids line up in the center of the cells in what is known as a centromere. A spindle then attaches to each chromatid and the cell divides, with one of the sister chromatids in each of the two new cells. At the end of this process, there are two cells identical to the initial cell.
Meiosis
Meiosis begins just as mitosis did with two chromosomes duplicating each other and creating sister chromatids. At the next stage the sister chromatids pair up and condense, with each swapping segments with its partner. It is this vital step that results in a shuffling of genetic information. As in mitosis the sister chromatids are aligned at the center, a spindle attaches to each and the cell splits, with two nonidentical pairs in each new cell. The centrioles now align again in the new cells, spindles attach and the cell splits again. The final result is four cells with non-identical chromosomes in each and each with half the chromosome number. These are the sex or gamete cells, on fertilization two of these gamete cells will fuse giving the full number of chromosomes. This is another way in which genetic information is shuffled.
The diagram below shows the process:
Source: Access Excellence. Mitosis Labeled Diagram. The National Health...
As can be seen in mitosis two identical cells are produced but in meiosis four cells are produced with varying genetic information.
2. Mating Pairs
A)
A homozygous dominant has a pair of dominant alleles, TT.
A homozygous recessive has a pair of recessive alleles, tt.
The genotypes for the offspring are shown below:
TT
- t Tt
- t Tt
Result is 4/4 Tt genotypes.
Because T. is the dominant allele, the phenotype is 4/4 T.
B)
A heterozygous has a pair of nonidentical alleles, Tt.
The genotypes for the offspring are shown below:
t T
- t tt
- T Tt
Result is 1/4 tt, 2/4 Tt and 1/4 TT genotypes.
Result is ae T. phenotypes (Tt and TT) and 1/4 t phenotype (tt).
C)
A heterosygous has a pair of nonidentical alleles, Tt.
A homozygous recessive has a pair of nonidentical alleles tt.
A heterozygous has a pair of nonidentical alleles, Tt.
The genotypes for the offspring are shown below:
T t
- t Tt
- t tT
Result is 2/4 tt and 2/4 Tt genotypes.
Result is 2/4 T. phenotypes (Tt) and 2/4 t phenotype (tt).
If the trait is X-linked one dose of the X-linked trait will cause the expression of that characteristic, meaning that the phenotype can be t, even when Tt is the genotype.
A)
A homozygous dominant has a pair of dominant alleles, TT.
A homozygous recessive has a pair of recessive alleles, tt.
The genotypes for the offspring are shown below:
TT
- t Tt
- t Tt
Result is 4/4 Tt genotypes.
Because't is an X-linked trait, t will be expressed, so the phenotype is 4/4 t.
B)
A heterozygous has a pair of nonidentical alleles, Tt.
The genotypes for the offspring…
Lawrence, Eleanor. Dictionary of Biological Terms. Essex: Longman Group Limited, 1996.
Marsden Brown, M. Introduction: Themes in the study of life. University of Dallas. 30 August 2001. <http://www.udallas.edu/biology/GenBio/Intro.html>
Starr, C and Taggart, R. Biology: The Unity and Diversity of Life. Belmont: Wadsworth, 1995.
In meiosis the chromosomes are reduced in half, with the phases being: Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II and Telophase II. Finally, mitosis creates all other cells with the exception of sex cells, while meiosis creates egg and sperm cells only (Meiosis vs. Mitosis, 2008) Phases -- Meiosis: 1) Meiosis 1 -- separates chromosomes in half; DNA is exchanged and chromosomes
The produced haploid daughter cells then develop further to form gametes (egg & sperm). In summary, meiosis consists of two nuclear divisions whilst mitosis is followed in one division though both of these processes involve the interphase, prophase, metaphase, anaphase and telophase stages. While mitosis is important in cell growth, tissues repair and several types of cells through asexual reproduction, meiosis is vital in developing the eggs and sperms through
Enzymes 1. How does temperature affect enzyme function? Every enzyme demonstrates maximum activity at a particular temperature known as its optimum temperature. Generally, all enzymes are inactivated at temperatures below 10°C and get denatured (lose its three-dimensional protein nature) above its optimum temperature (Seager & Slabaugh 2010). Experiments conclude that enzyme activity increases by almost ten percent coupled to each degree rise in temperature until it reaches its optimum state and declines beyond
Carbon cycles through the ecosystem between the atmosphere, organisms (such as producers, herbivores, and carnivores) and decomposers. This natural cycle maintains a somewhat constant level of carbon in the atmosphere. The burning of fossil fuels releases carbon into the cycle that has been trapped inside the earth. How does this affect the cycle and what problems can this cause? The two main processes of the carbon cycle are photosynthesis and metabolism.
Genetics Student Response Original DNA Strand: 3'-T ACCCTTTAGCCACT-5' Transcription (base sequence of RNA): 3'-A UGGGAAAUCGGUGA-5' Translation (amino acid sequence): Met -- Gly -- Asn -- His -- Arg -- STOP Mutated gene sequence one: 3'-T ACGCTTTAGCCATT-5' Transcription (base sequence of RNA): 3'-A UGCGAAAUCGGUAA-5' Translation (amino acid sequence): Met -- Arg -- Asn -- His -- Arg -- STOP Mutated gene sequence two: 3'-T AACCTTTACTAGGCACT-5' Transcription (base sequence of RNA): 3'-A UUGGAAAUGAUCCGUGA-5' Translation (amino acid sequence): Ile -- Gly -- Asn -- Asp -- Pro-STOP What is the significance of the
Genetics Original Gene Sequence: 3'-T AC CC T. TT AGTAGCCAC T-5 Transcription of Original: 3'-A UG GG A AA UCAUCGGUG A-5' Translation of Original: Start codon Met, Gly, Asn, His, Arg, Stop Mutated Gene Sequence 1: 3'-T ACGCT TT AGTAGCCAT T-5' Transcription of Mutated 1: 3'-A UGCGA AA UCAUCGGUA A-5' Translation of Mutated 1: Start codon Met, Arg, Asn, His, Arg, Stop Mutated Gene Sequence 2: 3'-T AACCT TT ACTAGGCAC T-5' Transcription of Mutated 2: 3'-AUUGGAAAUGAUCCGUGA Translation of Mutated