What is the term used to describe the number of chromosomes in each of the gametes produced during meiosis?
Answer is Haploid Explanation: Haploid: refers to the presence of single set of chromosome eg: Gametes, bacterium Diploid: refers to the presence of two sets of chromosome. eg: our body cells Let us take the example of ours Chromosome number=46 (diploid) As a result of meiosis in germ cells: Egg 23 chromosome (haploid)+ sperm 23 chromosome (haploid)=Zygote 46 chromosomes (diploid) In egg and sperm, there is only one copy of a gene. That is why it is haploid. The resultant zygote 23+23=46 chromosomes (diploid) 23 from the father's sperm and 23 from the mother's egg. Each chromosome is represented twice that is why zygote and all other body cells formed from zygote are diploid.
Describe the structure of bacteria.?
In general, a bacterium has cell wall, cell membrane and cytoplasm. As they are prokaryotes, bacteria do not tend to have membrane-bound organelles in their cytoplasm and thus contain few large intracellular structures. They consequently lack a nucleus, mitochondria, chloroplasts and the other organelles present in eukaryotic cells, such as the Golgi apparatus and endoplasmic reticulum. Instead their cytoplasm contains nucleoid, ribosome, carboxysome etc. Bacteria also may have appendages like flagella or pili. You can get more details here: http://textbookofbacteriology.net/structure.html http://www.smartymaps.com/map.php?s=prokaryote http://en.wikipedia.org/wiki/Bacteria#Cellular_structure
Which statement best describes a eukaryotic chromosome?
1) c 2) d 3) e 4) b 5) c 6) a 7) a 8) e 9) c 10) a
Major differences between bacterial chromosomal DNA and plasmid DNA?
chromosomal DNA is the DNA found in the bacterium naturally. Plasmid DNA is usually introduced into the cell by other bacterium during conjugation or it can be inserted by a viral vector. Plasmids can be created by humans by recombinant DNA.
How does bacteria acquire new genes?
Transduction: Movement of DNA from one bacteria to another by a virus. Conjugation: Kinda of like sex for bacteria. DNA on a specilized plasmid (a circular piece of DNA not part of the chromosome) moves from a donor bacteria to a recipient bacteria. Transformation: Bacterial cells picking up naked DNA from their environment. All three mechanisims can allow a bacteria to pick up genes from it's environment.
How do bacterial cells differ from human cells?
Cellhuman cells: are in a group and not isolated. It is dependent on other cells for survival.bacterial:Cell is isolated and Independent. It survives as an individual on its own.Cell wall hashuman:Cytoplasmic bridges are present which help in inter-cellular transport in between neighboring cells.bacterial:No cytoplasmic bridges as there is only one cell.Cell shapehuman:Only spherical or oval.bacterial:Cells can be of different shapes.RNA (ribo nucleic acid)human:80 s type with 60 s and 40 s sub units.bacterial:70 s type with 50s and 30s type sub units.Reproductionhuman:Asexual reproduction only.bacterial:Both sexual and asexual reproduction happens.Cell division occurs byhuman:All cells undergo mitosis. Only ovum and sperm formation by meiosis. While nerve cells never divide.bacterial:Mitosis and meiosis. Mitosis gives two cells and meiosis gives fur cells.Movementhuman:Cannot move, except for sperm and ova. While blood cells flow in the fluid.bacterial:Can move on their own with flagella for normal needs.Nutritionhuman:Heterotrophs. Depends on the food supplied by blood from body gut.bacterial:Autotrophic, heterotrophic, parasitic etc. Autotrophs manufacture their own food. Disease causing bacteria are parasites & live on other organisms.Cell deathHuman cell is mortal. Cell dies by either apoptosis or necrosis.Bacterial cell is immortal. It never dies unless sterilized. Divides for new offspring’s. Even in harsh conditions it tries to survive as spore form (dormant).
What is the difference between bacterial dna and human dna?
Human DNA is contained in 46 linear chromosomes, which are housed inside the nucleus. Each DNA molecule has proteins called histones associated with it; the DNA double helix wraps around octamers of histones to form nucleosomes, and a nucleosome typically occurs about every 200 nucleotides. This DNA-histone combination has the appearance of beads along a thread, and is called chromatin. In the S phase of interphase, each of the 46 chromatin fibers in a human cell are duplicated and the two identical copies of each chromosome are linked together. Later, in prophase of mitosis, the chromatin begins condensing - it becomes folde, coiled, thicker, and shorter, forming visible structures. Each chromosome then consists of 2 sister chromatids - these are just the 2 identical copies of chromatin that resulted from duplication, but in a condensed (as opposed to dispersed) form. The haploid human genome (consisting of 23 chromosomes) contains about 3.2 billion base pairs, which means that the average human chromosome contains about 139 million base pairs. Eukaryotic cells - which includes human cells - also have lesser amounts of DNA in their mitochondria. And for those eukaryotes that have them, chloroplasts also contain DNA. Bacteria typically store their DNA in a single, circular chromosome, which is located in the nucleoid (prokaryotes, such as bacteria, do not have a true nucleus). However, some bacteria have multiple chromosomes, and some bacteria also have linear chromosomes. The DNA of bacteria is not associated with histones; however, there are analogous proteins around which the DNA wraps. Compared to a human chromosome, a bacterial chromosome is typically much smaller. For example, the chromosome of E. coli contains only about 4.6 million base pairs compared to the average human chromosome's 139 million. In addition to the bacterial chromosome, many bacteria also have smaller, circular DNA molecules called plasmids in their cytoplasm.
What is bacterial cytoplasm?
It is a gel like matrix composed of water, enzymes, nutrients, wastes and gases and contains cell structures such as ribosomes, a chromosome and plasmids. Bacteria unlike eukaryotic organisms, do not have a membrane enclosed nucleus.It aids the movement of cellular materials and transports the genetic material and products of cellular respiration. It stores the chemicals and nutrients and gives shape to the bacteria.