During metaphase, the chromosomes line up across the center of the cell. Each chromosome attaches to a spindle fiber at its centromere. During anaphase, the centromeres split, the two chromatids separate, and each chromatid becomes a new chromosome. During the last part of mitosis —— telophase, the chromosomes begin to stretch out and lose their rodlike appearance. A new nuclear envelope forms around each chromosomes.
c. What would be the sequence of the mRNA after this sequence is transcribed? d. How many amino acids does this portion of Henry's coding stand actually code for? In the first mutation of the CYP2C9 gene described in Henry's story, the 1075th nucleotide has been changed from an adenine (A) to a cytosine (C). This mutation converts an ATT triplet code in the coding strand of the DNA molecule to CTT. Beginning with this triplet code on the DNA, describe the effect that this change would have on the following: a.
Chromosomes are copied, DNA synthesized, Organelles manufactured, centrioles replicated, Now the cell’s ready to divide. Mitosis is S, and in it things are quick, Four phases together do the trick. Prophase, Metaphase, Anaphase, and Telophase In prophase, chromatids coil and chromosomes form, Centromeres holding duplicated chromosomes are the norm. Each coiled chromosome has two sister chromatids, Nucleus begins to disappear, centrioles moves out, and spindles created. Metaphase is the shortest stage.
Comparison chart | Meiosis | Mitosis | Definition: | A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes in a diploid cell. | A process of asexual reproductionin which the cell divides in two producing a replica, with an equal number of chromosomes in haploid cell | Function: | sexual reproduction | Cellular Reproduction & general growth and repair of the body | Type ofReproduction: | Sexual | Asexual | Occurs in: | Humans, animals, plants, fungi | all organisms | Genetically: | different | identical | Crossing Over: | Yes, mixing of chromosomes can occur. | No, crossing over cannot occur.
The first step in protein synthesis is the transcription of mRNA from a DNA gene in the nucleus. The other types of RNA have been synthesized using the DNA. The RNAs migrate from the nucleus into cytoplasm. The second step of protein synthesis is actually initiated by the AUG codon on mRNA. The AUG codon signals both the interaction of the ribosome with mRNA and also the tRNA with the anticodons UAC.
4)Telophase- final phase of mitosis, it starts as soon as chromosome movement stops, two identical set of chromosomes are at opposite poles of the cell, a nuclear envelope forms, nucleoli reappears, and the spindle disappears we are left with one cell and two identical nucleus. In late anaphase, cytokinesis which is the last part of the cell cycle at the mitotic phase begins. It divides the cytoplasm and we are now left with two identical daughter
Having two sets of chromosomes is known as (2n) _______diploid___________. ANSWER: 6. Eggs and sperm are _______haploid_________ (n). ANSWER: Next Give one characteristic of each of the following phases of Meiosis I. Prophase I: During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis Metaphase I: Bivalents, each composed of two chromosomes align at the metaphase plate Anaphase I: Each of the daughter cells is now haploid Telophase I: Nuclear envelopes may reform 7. Does the S phase (DNA replication) occur after Meiosis 1?
Or each chromosome of a pair can be individually picked. 16. Explain two ways in which children can have different chromosomes (gene variation) than their mother or father. Random separation of chromosomes (law of segregation) when forming sperm/ova during anaphase I, crossing over of some genes to the homologous chromosomes during prophase I, and mutation during S
Sometimes single proteins other times groups of proteins which account for the phenotype of an organism All organisms begin life a single cell. In the case of humans the cell contains one set of chromosomes contributed by the mother, and one set of chromosomes contributed by the father, all of which contain DNA from the respective parent and carry genetic information that will be passed on to the offspring. As the fertilized egg divides and the cells are instructed by the DNA to differentiate to become all of the different cell types required by the human, the DNA molecules of the fertilized egg must be duplicated over and over, so that each of our trillions of cells contains an exact copy of the DNA contained in the fertilized egg. DNA replication must be tremendously accurate to ensure that
Telophase I • A nuclear membrane forms around the chromosomes at each pole and chromosomes uncoil • The cell undergoes cytokinesis to form two daughter cells • Forms two haploid cells • At the end of telophase I the cells may enter a short interphase period or proceed directly to meiosis II • DNA is not replicated Meiosis II Prophase II • Chromosomes coil up again • Centrioles move to the cell poles • Nuclear membrane disintergrates Metaphase II • Spindle fibers attach to the the centromeres • Chromosomes align along the equator Anaphase II • Spindle fibers shorten • Centromeres split • Chromatids of each chromosome travel to opposite poles Telophase II • Nuclear membrane forms around the chromatids at each pole, once the membrane is formed, each chromatid is then called a chromosome. • Both cells undergo cytokinesis to form four cells • Chromosomes uncoil • Nucleoli form 10.1.2 Outline the formation of