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3 years ago

Pls help<3 What is the end result of crossing-over during the first stage of meiosis?

Biology

2 answers:

zimovet [89]3 years ago

6 0

Answer:

Explanation:

Because the chromatids now contain little bits of DNA from one another they aren't identical. hope it helps

Xelga [282]3 years ago

6 0

Answer:

Mark me as brain list

Explanation:

During crossing over, part of one chromosome is exchanged with another. The result is a hybrid chromosome with a unique pattern of genetic material. Gametes gain the ability to be genetically different from their neighboring gametes after crossing over occurs.

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Nuestro planeta esta habitada por numerosas ____, muchas de ellas extendidas en grandes y diversas zonas. Sin embargo, existen e

FinnZ [79.3K]

Answer:

Nuestro planeta esta habitada por numerosas especies, muchas de ellas extendidas en grandes y diversas zonas. Sin embargo, existen especies que habitan una sola área/región con características ambientales únicas para su desarrollo.

Explanation:

Entre las miles de especies que habitan el planeta, muchas de ellas pueden estar ampliamente distribuidas, mostrando adaptaciones a una gran variedad de ambientes y hábitats, mientras que muchas otras solo se encuentran restringidas a determinadas areas o regiones particulares que presentan condiciones ambientales determinadas. Esta diferencia en distribución esta muy relacionada a la historia de la especie, a la edad de la misma sobre la tierra, adaptaciones a los ambientes y capacidades reproductivas y de dispersión.

Dentro de la clasificación de especies de acuerdo a su distribución, podemos mencionar a las especies

nativas: aquellas que habitan y se distribuyen las áreas naturales donde se originaron,
endemicas: entran dentro del concepto de nativas, pero a parte se caracterizan por habitar unicamente una región en particular debido a las condiciones ambientales que les son propicias para su desarrollo. Estas especies no pueden trasladarse a otras regiones.
exoticas: aquellas especies que salen de su area natural de distribución para habitar otras areas mas lejanas. Allí pueden establecerse e interactuar con especies nativas sin causar grandes daños.

invasoras: especies exoticas que llegan a otras areas, que se establecen y que tienen la capacidad de reproducirse a una tasa superior a la de las especies nativas, invadiendolas y desplazandolas. Interactuan con las especies nativas y causan daños importantes.

Los términos nativos, endemicos, exóticos son relativos al área a la que se esté haciendo alusión: un continente, un país, una región o un bioma.

5 0

3 years ago

In pea plants, long stems are dominant to short stems, purple flowers are dominant to white, and round peas are dominant to wrin

meriva

Assuming the genes are not linked nor interacting with each other, the expected number of long stemmed plants with purple flowers, producing wrinkled peas, L-P-rr, is 288.

<h3>Available data</h3>

long stems are dominant to short stems
purple flowers are dominant to white,
round peas are dominant to wrinkled

Each trait is determined by a single, different gene.

A heter0zyg0us plant is self-crossed
F1) 2,048 descendants

Let us name te alleles as follows

L ⇒ Long stem
l ⇒ Short stem
P ⇒ Purple flowers
p ⇒ white flowers
R ⇒ Round peas
r ⇒ wrinkled peas

Cross) heter0zyg0us plant is self-crossed

Parental) LlPpRr

Gametes) LPR, LPr, LpR, Lpr, lPR, lPr, lpR, lpr

Assuming that these genes are not linked nor interacting with each other, to make the calcs easier we will make crosses considering each gene separately.

Stems

Parental) Ll x Ll

F1) 1/4 LL, 2/4 Ll, 1/4 ll

3/4 long stem, 1/4 short stem

Flower color

Parental) Pp x Pp

F1) 1/4 PP, 2/4 Pp, 1/4 pp

3/4 purple flowers, 1/4 white flowers

Peas

Parental) Rr x Rr

F1) 1/4 RR, 2/4 Rr, 1/4 rr

3/4 round peas, 1/4 wrinkled peas

Now, we will get the proportion of individuals with long stems, purple flowers, producing wrinkled peas, L-P-rr

Note: The symbol - is representing either a dominant or a recessive allele.

From the crosses, we know that

3/4 are long stemmed,
3/4 have purple flowers, and
1/4 have wrinkled peas.

To get the proportion of individuals expressing all these traits together, we just need to multiply these values.

3/4 L- x 3/4 P- x 1/4 rr = 9/64 L-P-rr

Knowing that the total number of plants is 2,048 and that there are 64 possible gametes combinations from this cross, we will use the proportion 9/64 to get the number of plants with these traits.

64 ------------- 2,048 plants

9 -------------- X = (9 x 2048) / 64 = 288 plants.

We expect to find 288 long stemmed plants with purple flowers, producing wrinkled peas.

You will learn more about trihybrid crosses at

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4 0

2 years ago

What would you do if you found out that you contracted a deadly bacterium/ virus?

gizmo_the_mogwai [7]

Answer:The plague is a serious bacterial infection that can be deadly. Sometimes referred to as the “black plague,” the disease is caused by a bacterial strain called Yersinia pestis. This bacterium is found in animals throughout the world and is usually transmitted to humans through fleas.

The risk of plague is highest in areas that have poor sanitation, overcrowding, and a large population of rodents.

In medieval times, the plague was responsible for the deaths of millions of people in Europe.

Today, there are only 1,000 to 2,000 casesTrusted Source reported worldwide each year, with the highest incidence in Africa.

Plague is a rapidly progressing disease that can lead to death if untreated. If you suspect you have it, call a doctor right away or go to an emergency room for immediate medical attention.

Types of plague

There are three basic forms of plague:

Bubonic plague

The most common form of plague is bubonic plague. It’s usually contracted when an infected rodent or flea bites you. In very rare cases, you can get the bacteria from material that has come into contact with an infected person.

Bubonic plague infects your lymphatic system (a part of the immune system), causing inflammation in your lymph nodes. Untreated, it can move into the blood (causing septicemic plague) or to the lungs (causing pneumonic plague).

Septicemic plague

When the bacteria enter the bloodstream directly and multiply there, it’s known as septicemic plague. When they’re left untreated, both bubonic and pneumonic plague can lead to septicemic plague.

Pneumonic plague

When the bacteria spread to or first infect the lungs, it’s known as pneumonic plague — the most lethal form of the disease. When someone with pneumonic plague coughs, the bacteria from their lungs are expelled into the air. Other people who breathe that air can also develop this highly contagious form of plague, which can lead to an epidemic.

Pneumonic plague is the only form of the plague that can be transmitted from person to person.

How plague spreads

People usually get plague through the bite of fleas that have previously fed on infected animals like mice, rats, rabbits, squirrels, chipmunks, and prairie dogs. It can also be spread through direct contact with an infected person or animal or by eating an infected animal.

Plague can also spread through scratches or bites of infected domestic catsTrusted Source.

It’s rare for bubonic plague or septicemic plague to spread from one human to another.

Explanation:

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3 years ago

What is groundwater?

Vera_Pavlovna [14]

Groundwater is the water found underground in the cracks and spaces in soil, sand, & rock.

8 0

3 years ago

Read 2 more answers

Rabbit fur color gene is hereditary. A heterozygous brown fur rabbit has baby rabbits with another heterozygous brown fur rabbit

valina [46]

Answer:

The answer is the odds are 1-in-4.

5 0

3 years ago