If meiosis II proceeds normally, each of the four gametes that result from that meiosis will have 20 chromosomes.
If a homologous pair undergoes non-disjunction during meiosis, then two cells will have an extra chromosome, and the remaining two cells will have one chromosome fewer.
In the first meiotic division of a germ cell, if a single homologous pair undergoes non-disjunction in meiosis, it means that they do not separate correctly.
Non-disjunction is defined as the failure of chromosomes to separate during cell division, resulting in an abnormal distribution of chromosomes in the daughter nuclei.
When non-disjunction occurs during meiosis I, the chromosomes remain attached, and all four daughter cells will have an abnormal number of chromosomes.
Non-disjunction can result in cells that have too many or too few chromosomes. If the pair of chromosomes does not separate properly in meiosis I, it will result in two cells having an extra chromosome, and two cells will lack one chromosome.
These cells are called aneuploid cells. An aneuploid cell is a cell that does not contain a multiple of the haploid chromosome number.
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do not add any more lactose and watch what transpires. note what happens and why this occurs. how could you re-activate the lacz gene?
The lacZ gene is responsible for the enzyme β-galactosidase which breaks down lactose. When no more lactose is added, the lacZ gene is not activated and the β-galactosidase enzyme does not break down lactose. To re-activate the lacZ gene, you would need to add lactose back in so that the β-galactosidase enzyme is activated and lactose is broken down.
Lactose is a disaccharide sugar composed of glucose and galactose, which is found in milk. Lactose can be hydrolyzed into glucose and galactose through the catalytic action of lactase enzymes. This reaction occurs in the small intestine, and the glucose and galactose are then absorbed and used as energy by the body.
When lactose is present, the lac operon is activated, and the genes involved in lactose metabolism are transcribed into messenger RNA. When lactose is absent, the lac operon is turned off, and these genes are not expressed.
To re-activate the lacZ gene, it is necessary to add lactose or a lactose analog such as IPTG to the culture medium. IPTG is an inducer of the lac operon that does not bind to the repressor protein, allowing the genes involved in lactose metabolism to be expressed even in the absence of lactose.
When lactose is present, the lac operon is activated, and the genes involved in lactose metabolism are transcribed into messenger RNA. When lactose is absent, the lac operon is turned off, and these genes are not expressed.
Therefore, if no more lactose is added to the culture medium, the lac operon will turn off, and the genes involved in lactose metabolism will not be expressed. This occurs because the repressor protein binds to the operator site of the operon, preventing RNA polymerase from transcribing the genes involved in lactose metabolism.
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Select the correct statement about absorptiona. 30% ingested materials have been absorbed by the end of the large intestine.b. carbohydrates diffuse across the villus epithelium and are then passively transported into blood capillaries.c. if intact fats are transported across the villus epithelium, an immune response may be generated.d. Amino acid transport is linked to sodium transport.The answer could be one choice or multiple choices
The correct statement(s) about absorption is (D) Amino acid transport is linked to sodium transport.
Amino acids are transported across the villus epithelium in the small intestine, and this process is linked to sodium transport.
Amino acids, not proteins, are absorbed; proteins rely on prior digestion to amino acids. Most absorption of amino acids occurs in the jejunum; there is a lesser contribution from the ileum.
Amino acids are absorbed by a co-transport mechanism with sodium ions. Both sodium ion and amino acid combine with a cell surface protein receptor.
There are different receptors for the groups: neutral amino acids, basic amino acids, acidic amino acids
In addition, certain amino acids may have there own specific transporter e.g. proline. The receptor then conveys both molecules to the inside of the cell.
The energy for this transport is derived from the concentration gradient for sodium across the cell membrane. Na-K ATPase transporters actively and continuously pump sodium ions outwards to maintain the gradient.
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onsuming foods with high glycemic index immediately after a bout of exercise will multiple choice question. ensure a slow rise in blood glucose. supply amino acids for muscle repair. rapidly restore glycogen stores. replenish sweat losses.
Consuming foods with high glycemic index immediately after a bout of exercise will c. rapidly restore glycogen stores.
Consuming foods with a high glycemic index such as boiled potatoes, white rice, white bread after exercise can quickly restore glycogen stores that are depleted during exercise. The glycemic index value depends on several factors, including dietary fiber content, amylose and amylopectin levels, fat and protein content, starch digestibility, and processing methods.
Glycogen is a storage form of glucose, where glucose is a simple sugar, a form of carbohydrates. Glycogen is an important fuel for athletes, because it is quickly broken down and used for energy.
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