1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
jeka57 [31]
3 years ago
12

A normal human karyotype has

Biology
2 answers:
omeli [17]3 years ago
8 0

A karyotype is the number and appearance of chromosomes in the nucleus of an eukaryotic cell. The term is also used for the complete set of chromosomes in a species or in an individual organism and for a test that detects this complement or measures the number.

What Is a Karyotype?

A karyotype is simply a picture of a person’s chromosomes. In order to get this picture, the chromosomes are isolated, stained, and examined under the microscope. Most often, this is done using the chromosomes in the white blood cells. A picture of the chromosomes is taken through the microscope. Then, the picture of the chromosomes is cut up and rearranged by the chromosome’s size. The chromosomes are lined up from largest to smallest. A trained cytogeneticist can look for missing or extra pieces of chromosome.

karyotype[1]There are 22 numbered pairs of chromosomes called autosomes.  The 23rd pair of chromosomes are the sex chromosomes.  They determine an individual’s sex.  Females have two X chromosomes, and males have an X and a Y chromosome.

How are the Chromosomes Numbered?

Each chromosome has been assigned a number based on its size. The largest chromosome is chromosome 1. Therefore chromosome 18 is one of the smallest chromosomes in humans.

Human karyotypes: 2n = 48 or 46?

   Early studies of the human karyotype simply stained chromosomes within cells with Giemsa and "squashed" them between the cover slip and slide. Most cells were not at the proper mitotic phase for chromosomes to be observed, and chromosome separation was poor. The exact count was uncertain: most workers accepted the number 48. The breakthrough came in 1952 (left) when a technician in the lab of T. C. Hsu accidentally substituted distilled water for the normal saline solution used in washing the cells just before "squashing". This "hypotonic" treatment caused the cell nuclei to swell, and allowed the chromosomes to separate before squashing. A further refinement was "dropping" the cells onto the slide at arm's length, which caused the nuclei to burst on impact, further separating them (middle slide). Finally, the use of a plant spindle-poison Colchicine allows chromosomes to be arrested at mitotic metaphase, during their maximum state of compaction [right] These experiments quickly established the human chromosome number as 2n = 46 chromosomes.  

   Classification of  chromosomes into seven groups by size and relative centromere position established the so-called "Denver System" (right) in 1960. Chromosomes within groups B - G were not readily distinguishable from each other. The X chromosome is in the C group, and the Y is in the G group: males are reconizable by five small G-type chromosomes. Modern banding techniques allow each chromosome in the karyotype to be distinguished individually.

Alborosie3 years ago
8 0
It has 46 chromosomes or 23 pairs. The last pair(23rd) would be the sex chromosomes which differ in men(xy) and women(xx).
You might be interested in
What would the complimentary RNA strand be if one of the strand's base sequence was:
goldfiish [28.3K]
T A C T T C A T A are the answers
3 0
3 years ago
Read 2 more answers
Saving lives with smelly feet (collect best ideas)?
Svetach [21]
With smelly feet, you can avoid people who are boring and dangerous (,like bullies),
4 0
2 years ago
How do fish increase lake carbon dioxide levels?
fiasKO [112]

Answer:

they dreath in water?

Explanation:

6 0
3 years ago
Read 2 more answers
What the effect of the light on plant what changes were caused by the sunlight
bekas [8.4K]
  • Plants use the carbon dioxide in air and water in presence of sunlight to form carbohydrates. and oxygen.

The reaction is given by

\\ \tt\hookrightarrow CO_2+H_20\overset{Sunlight}{\longrightarrow}C_6H_{12}O_6+O_2

6 0
2 years ago
Read 2 more answers
2. A lunar eclipse can occur when the Moon is in......in its orbit.
Natali5045456 [20]

Explanation:

It happens when the moon is in the earth's shadow

And sun moon and earth is completely aligned

6 0
3 years ago
Read 2 more answers
Other questions:
  • Which statement is true about a cell? A. They can only reproduce by budding. B. They do not pass on genetic traits. C. All organ
    15·1 answer
  • Barnacles are organisms that live in aquatic environments and live stationary lives attached to hard surfaces. Their feathery ap
    15·1 answer
  • Which planets are often called the terrestrial planet's<br>​
    9·2 answers
  • Why is a lumbar puncture performed between the L4 and L5 vertebrae
    14·1 answer
  • What holds and protects DNA
    9·1 answer
  • A lizard sitting on a rock would be considered the level of organization.
    7·1 answer
  • HELP!!!
    7·1 answer
  • Using the letter l for Lovingston’s and I for non Lovington,s, determine kites and dots genotypes and then complete the punnet s
    14·1 answer
  • Photosynthesis inputs
    13·1 answer
  • Which of the following describe Angiosperms? (select all that apply)
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!