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Nookie1986 [14]
3 years ago
10

What is the external stimulus in thigmotropism?

Biology
1 answer:
irina [24]3 years ago
6 0

Answer:

Thigmotropism is defined as a negative or positive directional response in a plant or part of a plant such as a plant organ, that is caused by an external stimulus such as touch or contact with any solid object. The factor that causes the stimulus is a hard surface that can change the direction of growth of the plant or part of the plant.  Hope this helps :)

Explanation:

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EXTRA POINTS **
allochka39001 [22]

Answer: i think the force will be a little smaller and the other force pulling left will be 0

Explanation:

6 0
2 years ago
It is usually easier to calculate an enzyme's reaction velocity from the rate of appearance of .............. rather than the ra
elena-14-01-66 [18.8K]

Answer:

It is usually easier to calculate an enzyme's reaction velocity from the rate of appearance of PRODUCT rather than the rate of disappearance of a SUBSTRATE. Enzyme activity is measured as an INITIAL reaction velocity, the velocity before much SUBSTRATE has been depleted and before much PRODUCT has been generated. It is easier to measure the appearance of a small amount of PRODUCT from a baseline of zero PRODUCT than to measure the disappearance of small amount of SUBSTRATE against a background of high concentration of SUBSTRATE.

7 0
3 years ago
How many chromosomes does a body cell for the organism (egg and sperm) have?
DiKsa [7]
Growth and repair
creation of gametes (sex cells)
method of reproduction in unicellular organisms
Binary Fission - type of reproduction that occurs in bacterial cells, single celled organism splits and becomes two identical organisms

Chromosomes and DNA

Chromosomes are DNA wrapped around proteins to form an X-shaped structure.



The diagram will help you see the relationship.

1. Chromosomes are found in the nucleus
2. Chromosomes are made of DNA
3. Sections of chromosomes are called genes



DNA - deoxyribonucleic acid (it is the genetic code that contains all the information needed to build and maintain an organism)





Chromosome Structure







Chromosome Numbers

Each organism has a distinct number of chromosomes, in humans, every cell contains 46 chromosomes. Other organisms have different numbers, for instance, a dog has 78 chromosomes per cell.

Somatic Cells - body cells, such as muscle, skin, blood ...etc. These cells contain a complete set of chromosomes (46 in humans) and are called DIPLOID.

Sex Cells - also known as gametes. These cells contain half the number of chromosomes as body cells and are called HAPLOID

Chromosomes come in pairs, called Homologous Pairs (or homologs). Imagine homologs as a matching set, but they are not exacly alike, like a pair of shoes.

Diploid cells have 23 homologous pairs = total of 46

Haploid cells have 23 chromosomes (that are not paired) = total of 23

Homologous Chromosomes



Sex Determination

Chromosomes determine the sex of an offspring. In humans, a pair of chromosomes called SEX CHROMOSOMES determine the sex.

If you have XX sex chromosomes - you are female

If you have XY sex chromosomes - you are male

During fertilization, sperm cells will either contain an X or a Y chromosome (in addition to 22 other chromosomes - total of 23). If a sperm containing an X chromosome fertilizes an egg, the offspring will be female. If a sperm cell containing a Y chromosome fertilizes an egg, the offspring will be male.

Creation of a Zygote

When two sex cells, or gametes come together, the resulting fertilized egg is called a ZYGOTE

Zygotes are diploid and have the total 46 chromosomes (in humans)

Karyotype

A karyotype is a picture of a person's (or fetus) chromosomes. A karyotype is often done to determine if the offspring has the correct number of chromosomes. An incorrect number of chromosomes indicates that the child will have a condition, like Down Syndrome

Compare the Karyotypes below













Notice that a person with Down Syndrome has an extra chromosome #21. Instead of a pair, this person has 3 chromosomes - a condition called TRISOMY (tri = three)

Trisomy results when chromosomes fail to separate - NONDISJUNCTION - when sex cells are created. The resulting egg or sperm has 24 instead of the normal 23.

Other conditions result from having the wrong number of chromosomes:

Klinefelters Syndrome - XXY (sex chromosomes)

Edward Syndrome - Trisomy of chromosome #13
4 0
3 years ago
Which hormone acts primarily on the uterus??
Monica [59]
Progesterone.
Hope this helps!
pls give Brainliest answer!
7 0
3 years ago
The concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function
ira [324]

Answer:

Astrocytes.

Explanation:

Astrocytes are the star shaped cells that are present in the brain and spinal cord. The exact constitution of astrocytes in the brain is not known and almost 20% to 40% astrocytes are present in brain.

The astrocytes acts as the blood brain barrier and involved in the process of brain scarring. Astrocytes also regulate ions concentration by propagating the calcium ion channels in response to the stimulus. Astrocytes also generate a response by the calcium dependent release of glutamate.

Thus, the correct answer is option (B).

7 0
3 years ago
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