Question 1

Predict phenotypes associated with nondisjunction of sex chromosomes.

Mnenie [13.5K]

Answer: The new daughter cells will have an abnormal amount of genetic material. That is called aneuploidy and it is the presence of an abnormal number of chromosomes. Different clinical conditions are the result of this nondisjunction.

Explanation:

Normal cells are diploids, that means they have two copies of each gene, one of each chromosome. So normal cells have two homologous chromosomes, one from each parent.

During anaphase of cell division, each pair of chromosomes is separated by the mitotic spindle. The separated chromosomes are then pulled by the spindle to opposite poles of the cell, and eventually will end up in the new daughter cells.

Nondisjunction is the failure of homologous chromosomes to separate properly during cell division, so it is the miss segregation of them. The new daughter cells will have an abnormal amount of genetic material. <u>Different clinical conditions are the result of this nondisjunction.</u>

Sex chromosomes participates in sex determination of an individual. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY) So nondisjunction of sex chromosomes could be:

XX: one cell with no chromosome and the other cell with two X chromosomes.
XY: one cell with no chromosomes and the other cell with XY chromosomes.

According to which gametes are fused during fertilization, different phenotypes can be given. For example, if a gamete with one chromosome fuses with another gamete with two chromosomes, the result will be an individual with three chromosomes (it could be XXY, or XXX) called trisomy.

Triple X syndrome is characterized by an extra X chromosome in females. Those affected are often taller than average, but most females have a normal sexual development. Klinefelter syndrome is known XXY individuals, and it causes infertility in males, breast growth, less body hair and weaker muscles.

And if a gamete with no chromosome fuses also with another gamete with no chromosome, the result is a nullisomy. But due to the lack of genetic material, the nullisomic gametes are rendered unviable for fertilization.

And if a gamete with no chromosome fuses with another gamete with one chromosome (normal) the result is a monosomy, the presence of only one chromosome from a pair. The result can be an individual who is X or Y. People with Turner syndrome have one X chromosome and it is the only monosomy that is seen in humans because other cases monosomy are lethal.

Any of those examples is called aneuploidy and it is the presence of an abnormal number of chromosomes.

3 0

3 years ago

Put the last 6 (Creep to Avalanche) in order from Fastest to Slowest.

kompoz [17]

Answer:

creep, solifluction, slump, earthflow, mudflow, debris avalanche, rockfall

Explanation:

Mass movement also known mass wasting is the motion of rock, regolith (loose mixture of soil and rock particles that covers the earth's surface), snow, and ice down a slope. Based on increasing speed of movement, the given mass movement processes are as follows:

Creep- this a very slow, usually continuous movement of regolith down slope.

Solifluction - this is a sediment flow. A sediment flow is a mixture of rock, regolith with some water. The rate solifluction is measured in centimeters per year. It occurs at a faster rate than than creep.

Slumps - is a type of mass movement whereby there is a downward rotation of rock or regolith along a curved surface producing depressions or scars on the slope. It occurs at a faster rate than solifluction.

Earthflows - they usually occur with heavy rains and occur at a much faster rate with velocities between several centimeters per year and hundreds of meters per day.

Mudflows- are a highly fluid mixture of sediment and water which usually result from heavy rains in areas where there is an abundance of loose sediment. These sediments are picked up by flowing streams of water. Mudflows occur at high velocities and can travel long distances.

Debris Avalanches - These are very high velocity mass movements that result from the complete collapse of a mountainous slope. Earthquakes and volcanic eruptions usually cause debris avalanches. Avalanches involving snow only is known as snow avalanches.

Rock Falls - Rock falls occur when a piece of rock which may be large or small on a steep slope comes loose and falls down the slope. On its way down it may dislodge other rocks which also fall down the slope. Rock falls are the fastest of the six types of mass movements stated.

7 0

3 years ago

Why "charge" reduces rate of diffusion in cell membrane

Over [174]

Answer:

Each ion or charged molecule in a fluid contributes to the fluid's overall electric charge. A difference in charge between two regions of fluid can affect the rate and direction of diffusion between them. For example, positively charged substances will tend to diffuse toward a region with an overall negative charge.

Explanation:

8 0

3 years ago

Which of the following processes occurs in G1 phase of the cell cycle?

TEA [102]

Answer:

c. the cells grow in size and content producing mainly proteins

5 0

3 years ago

How are hormones produced by endocrine glands typically transported to target cells?

ankoles [38]

Hormone Signaling. The glands of the endocrine system secrete hormones directly into the extracellular environment. The hormones then diffuse to the bloodstream via capillaries and are transported to the target cells through the circulatory system.

3 0

3 years ago