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JulsSmile [24]
3 years ago
9

A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in t

he ball’s path does it experience zero velocity and nonzero acceleration at the same time?
Biology
1 answer:
Georgia [21]3 years ago
6 0
The apex of the throw, which is when the ball reaches the highest part of the thrown before it begins to fall
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How many gallons of oil are in a barrel
Lina20 [59]
42 liquid gallons :)
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3 years ago
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Hemophilia is a condition in which blood does not clot naturally, and a person with hemophilia could bleed to death if injured.
barxatty [35]

As we know our blood has four main components which are plasma, red blood cells, white blood cells and platelets. That is why a hemophiliac must receive regular injections of platelets to stay alive. This is done by injecting into their bloodstream human plasma which contains many proteins, glucose, clotting factors, electrolytes, hormones, and carbon dioxide.


<span>I hope it helps, Regards.</span>

5 0
3 years ago
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____ 15. which excretory organ eliminates water and some chemical wastes in perspiration?
Nastasia [14]
I think the answer is skin. Skin contains sweat glands which secrete a fluid waste called sweat or perspiration; nonetheless, its primary functions are temperature control and release of pheromone. Its role as a part of the excretory is therefore minimal. Additionally, sweating also maintains the levels of salt in the body.
8 0
4 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
4 years ago
Define the 3 signals for activation and the 3 outcomes of the complement system.\
sp2606 [1]
* More than 40 proteins and glycoproteins involved in the complement system are synthesized by the liver, macrophages, epithelial cells, they are present in the blood in plasmatic form, membrane, some have an enzymatic activity, regulator or membrane receptorThese are elements of the humoral innate immune response, they fight infections, purify immune complexes and apoptotic bodies.
<span>There are indeed three ways to activate the complement:</span>
Classical pathway: Activated by Immunoglobulins in immune complexes, aggregated Immunoglobulins, DNA, CRP, apoptotic bodies .......it involves nine fractions, starting with C1, then C4, C2, C3, to form a classical C5 convertase, then, activation of C5, C6, C7, C8, C9.

Alternative pathway: activated by polysaccharides (bacterial endotoxin), vascular wall poor in sialic acid, aggregated IgE ...C3b like is the first component in the alternate channel cascade, it will create an amplification loop, and form an alternative C5 convertase.

Lecithin pathway: Activated by mannose, fucose (carbohydrate of microorganisms)The first component is the complex MBL / MASP1 / MASP2: "mannose-binding protein": works according to the same principle as the complex C1 of the classical way (MASP2 cleaves the C4 and the rest of the cascade is equivalent to that of the classical way).

the three ways have the same outcome: A C5 convertase (formed by one of the pathways) cleaves C5 into C5a and C5b: C5b is deposited far from other fractions on the antigenic surface. The fixation of C5b in the cell is followed by that of C6, C7, C8, and C9 (9 molecules of C9): formation of the membrane attack complex (MAC) ==> Death of the cell by osmotic shock
8 0
4 years ago
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