7. An extremely rare X-linked recessive genetic disorder known as Norrie disease affects the eyes
and can lead to blindness and in some cases hearing loss. There are only 400 known cases of
Norrie disease worldwide. Explain why it is virtually impossible for a baby girl to be born with
Norrie disease.

Answers

Answer 1

Answer: Girls need to inherit two affected chromosomes to develop the disease, and it may also happen that the affected chromosome is inactivated in the eye (if it has only one)

Explanation:

Norrie's disease is an inherited eye disorder affecting males, which is characterized by abnormal or immature development of the retina (light-sensitive nerve tissue lining the back of the eye) and possible deterioration of the iris (colored part of the eye) and eyeballs. X-linked recessive inheritance is one of the ways in which a genetic trait or condition is passed from parent to child when there are mutations in a gene on the X chromosome from either the father or the mother. Females possess two X chromosomes, while males possess one X and one Y chromosome. In males, the presence of a mutation on the X chromosome causes the disease, since it is the only X they possess. In females, both X chromosomes need to be affected if it is a recessive condition.

So, the disease is inherited in an X-linked recessive manner, which means that almost all affected individuals are male. However, the sons of affected males will not have the mutation since they only inherit the Y chromosome, while all their daughters will be genetic carriers of the mutation because they inherit the affected X chromosome, although without clinical symptoms but being carriers. On the other hand, the mother will pass one of her two X chromosomes (which may or may not be affected) randomly to both her male and female offspring (if they are male, they will be affected and if they are female they will be carriers unless they also inherit an X chromosome from their father). So the only way for females to develop the disease is for their two copies of the gene to be mutated if both parents have the mutation.

But female carriers could be affected by inactivation of their X chromosome with the correct sequence. X chromosome inactivation is a random process that happens separately in individual cells during embryonic development. That is, one cell may inactivate the paternal X chromosome, while others may inactivate the maternal X chromosome. This is because a dosage compensation is necessary, since the Y chromosome in males is not homologous to the X, it does not have the same genes, so if females would express both X chromosomes, they would have twice as many genes as a male.  All the descendant cells of each of these original cells will maintain the same pattern of X chromosome inactivation.

In females, one X chromosome is inactivated in each tissue in an arbitrary manner. Then, in addition to having to inherit two affected chromosomes, it may also happen that the affected chromosome is inactivated in the eye (if it has only one).


Related Questions

True or false larger cell function better than smaller cells

Answers

Answer:

FLASE

Explanation:

BECAUSE IN SMALLER CELL THE NEUCLUS IS MORE ACTIVE

How did adding a word change the possibilities?

Answers

Answer:

suffixes

Explanation:

June 22, 2018. A suffix is a letter or group of letters you add to the end of a word. It changes the meaning or function of a word. ... There are many suffixes used in the English language.

What kingdom is the Dandelion in?

animal

protist

fungus

plant

Answers

Plant kingdom is where the dandelion is in

Answer:

D. Plant

Explanation:

Dandelion is a plant with yellow flowers. If the flower is a plant then it would be in the plant kingdom. Flowers aren't animals, nor protists. Protists are organisms that are part of the biological kingdom called the protista. These organisms are not plants, animals, bacteria, or fungi. Fungi (Fungus) are like mushrooms and other types of things like that who feed on dead organisms. Flowers don't feed on dead organisms. So that leaves the plant kingdom.

Hope this helps! :3

Pietro has two dogs that are related, and he wants to understand why one of the dogs has tan fur and the other has brown fur.

Which pattern of inheritance would explain the different fur color in the related dogs?
polygenic inheritance
codominance
incomplete dominance
quantitative inheritance

Answers

Answer:

A

Explanation:

Just finished the quiz

Inheritance is defined as the transmission of genetic information from the parent to the offspring. The pattern of inheritance can be polygenic, incomplete, co-dominant, or quantitative.

The correct answer is:

Option A. polygenic inheritance

Polygenic inheritance is defined as the controlling of one trait by two or more genes. The phenotypic traits of an organism are influenced by one or more than one gene.

In the case of dog fur, the relative dogs have brown and tan fur that is due to polygenic inheritance. Thus, it determines the fur color of the dogs is controlled by more than one gene that can completely influence the phenotypic traits.

Therefore, the correct answer is polygenic inheritance.

To know more about polygenic inheritance, refer to the following link:

https://brainly.com/question/1984685

Scientists who study biogeochemical cycles often use the term fixation to describe converting an element from gaseous form in the atmosphere to solid form in the biosphere. For example, in the nitrogen cycle, bacteria are said to fix nitrogen by converting N2 gas into nitrates and nitrites in the soil that are later used to make organic macromolecules such as proteins and nucleic acids. There are many processes involved in cycling carbon, but only one is able to fix carbon from its gaseous form in the atmosphere to solid form in the biosphere. Which process performs carbon fixation

Answers

Answer:

Photosynthesis

Explanation:

Carbon fixation refers to the process by which elemental carbon in gaseous form in the atmosphere is converted to a solid form in living organisms. It is part of the larger process known as the carbon cycle. The carbon cycle is a very important cycle which involves the different steps by which carbon is exchanged between living organisms and their environment. The carbon cyclemis divided into the biological carbon cycle and the biogeochenpmical carbon cycle. The biological carbon cycle is the rapid exchange of carbon among living things while the biogeochemical cycle refers to the much slower cycle by which carbon is stored and released from carbon reservoirs in the environment.

In nature, carbon fixation occurs in the process of photosynthesis. During photosynthesis, green plant ( autotrophs) in the presence of sunlight as an energy source uses carbon present in air as carbon dioxide together with water vapour to produce organic biomolecules known as simple sugars which are also stored as starch. The products of photosynthesis are then used by heterotrophs, to return carbon in the form of carbon dioxide back to atmosphere.

3. How are frog eyes different from human eyes?​

Answers

Answer:

Most frogs see well only at a distance, but they have excellent night vision and are very sensitive to movement.This peripheral vision helps them spot predators and prey. Humans and other mammals focus images by changing the shape of the lens. Like a camera lens, frog eyes focus by moving the lens back and forth.

Can an animal live in only one habitat?
yes
no

Answers

Answer:

No

Explanation:

it depends on the animal but I would go with no

true or false? Body parts that share a common function but not common structure are called analogous structures.

Answers

The answer to this question is True

describe and explain how the structure of small intestine is adapted gor absorbing digested food
answer - Th​

Answers

Answer:

the small intestine has villi .

the villi project into the intestinal cavity, greatly increasing surface area for absorption of food and adding digestive secretions

Explanation:

hope it helps

what niche do you think you have in your family?​

Answers

Answer:

My brother is extremely artistic and can draw and animate really well. hes the arts while im the brains. Is that a niche lol?

Biotic and abiotic factors affect population density and dispersion. A) Explain the factors that affect a population's density. B) Describe the types of population dispersion, with examples, and the factors that influence them.

Answers

Answer:

Water supply, climate, shape of the land, vegetation, soils and availability of natural resources.

Explanation:

Water supply, climate, shape of the land, vegetation, soils and availability of natural resources are the factors that affect population density of an ecosystem. There are three types of population dispersion are uniform dispersion, random dispersion, and clumped dispersion. In uniform dispersion, individuals of a population are more or less evenly distributed for example, allelopathy plants. In random dispersion, individuals are distributed randomly in the ecosystem for example, dandelions plants. Clumped dispersion is when individuals in a population are clustered together for example, oak trees.

hey could someone pls help me with this immediately!! i’ll mark brainiest if u don’t guess or leave a link!

Answers

It involve both experimentation and repeated observations

Which cell has the highest surface area to volume ratio so that molecules pass through the cells very fast in the figure below that represents four hypothetical cells?

Answers

Answer:

A

Explanation:

What connective tissue is found in joints and provides a
smooth surface for bones to move against?

Answers

The answer is cartilage it’s a connective tissue, It’s filled with protein fibers that provide a smooth surface for bones to move against.

9. Which of the following best describes artificial selection?
It is the process by which plants have evolved to fill in ecological niches over time.
O
It is the process of manipulating genes in a lab to meet human needs
It is how animals are trained to do ticks
It is when humans chose beneficial traits in each generation of a spices
O It is when plants and animals chose to meet human needs

Answers

Answer:

It is when humans chose beneficial traits in each generation of a species.

Explanation:

Artificial selection is the process in which humans use animal and plant breeding to develop specific traits by choosing a particular animal or plant males and females which sexually reproduce and have offspring together. This selection is done in order to achieve a plants or animals with desired physical characteristics. This selection will leads to the production of best traits organisms for the future.

what is photosynthesis ?​

Answers

the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.

Answer:

Photosynthesis is the physical process in which plants make their food with the help of biotic and abiotic components.

what is the displacement​

Answers

Answer:

according to Byjus;"Displacement is defined as the change in position of an object. It is represented as an arrow that points from the starting position to the final position"

Explanation:

hope this is helpful

What extra part does a bird's egg have?

Answers

Stretchy membrane layers.

A species is transported to a new ecosystem. The new ecosystem is highly resilient, with a high number of different species. Which is MOST likely to happen to the new species?​

Answers

Answer:

The new species will eventually adapt to their new environement.

Explanation:

how the cells in your body are different from one another. Look at the different types of cells above, and make a list of how they differ. After you have made your list, consider why they have these differences.

Answers

Answer: Different cells have different jobs to do. Each cell has a size and shape that is suited to its job. Cells that do the same job combine together to form body tissue, such as muscle, skin, or bone tissue. Groups of different types of cells make up the organs in your body, such as your heart, liver, or lungs.Differentiation means that one cell performs a different function than another cell, depending on where it is in your body. ... All the cells contain the same genetic material and all of them are from one original cell that started as a fertilized egg, but they look different and act different from one another. Under a microscope, fat cells look like bulbous little spheres. Like other cells in the body, each has a cell membrane and a nucleus, but their bulk is made up of droplets of stored triglycerides, each of which consists of three fatty-acid molecules attached to a single glycerol molecule. Skin cells are specialized to be quickly shed and replaced, and do not have much mitochondria (which helps produce energy). Muscle cells, conversely, have lots of mitochondria because they need energy to produce movement. Unlike many other cells, red blood cells have no nucleus and can easily change shape, helping them fit through the various blood vessels in your body. Unlike most other eukaryotic cells, mature red blood cells don't have nuclei. When they enter the bloodstream for the first time, they eject their nuclei and organelles, so they can carry more hemoglobin, and thus, more oxygen. Each red blood cell has a life span of around 100–120 days. Skin cells are specialized to be quickly shed and replaced, and do not have much mitochondria (which helps produce energy). Muscle cells, conversely, have lots of mitochondria because they need energy to produce movement. brainliest??

Explanation:

I don’t understand it, if someone can explain maybe what I have to do and put into each Column or give me the answer either way would help a lot. Thank you.

Answers

Answer:

First, describe each type of evidence (eg. Molecular biology is comparing DNA sequences to determine common ancestry). Then provide examples of how those pieces of evidence support the theory of evolution. For example, for one of the comparative anatomy examples, you could say that organisms that contain similar structures most likely diverged from a common ancestor.

I hope this gets you on the right track.

Explanation:

In a given year, which would result in the greatest increase in population size?

A. high birth rate, high death rate, high immigration, high emigration
B. high birth rate, zero death rate, high immigration, zero emigration
C. zero birth rate, low death rate, zero immigration, low emigration
D. zero birth rate, zero death rate, low immigration, high emigration

Answers

B would definitely result in population rise.

Answer:

B. High birth rate, zero death rate, high immigration, zero emigration

Explanation:

High birth rate would mean more people being born resulting in a higher population. Zero death rate would mean that no one is dying and leaving the population. Immigration means when people come to a foreign country to live there, meaning that the population would grow. Emigration means the opposite of immigration. So that would mean that the people would be leaving your country. Resulting in a lower population. So, B is the correct answer!

Hope this helps! :3

What international agreements International purposes of peace and scientific research?

Answers

Answer: Antarctic treaty system is an international agreements of peace and scientific research signed in Washington on December 1, 1959 with 12 signatories.

Explanation:

Answer:An agreement between 50 nations allowing them to use the continent Antarctica for scientific research purposes

Explanation:

biology

Question:what is spermatogenesis​

Answers

Answer: the production or development of mature spermatozoa

Explanation: Hope this helps Plz mark me brainliest

SpongeBob loves growing flowers for his pal Sandy! Her favorite flowers, Poofkins, are found in red, blue, and purple. Use the information provided and your knowledge of incomplete dominance to complete each section below.



1. Write the correct genotype for each color if R represents a red gene and B represents a blue gene.

Answers

Answer:

Red=RR

Blue=BB

Purple=RB

Where a disturbance did not completely wipe out all life and nutrients from the environment, secondary succession occurs and homozygous.

Thus, Despite the fact that fire, flooding, and other disturbances can leave a landscape in ruins, drive many animals and plants away, and bring the biological community back to an earlier stage, the habitat is still alive because the soil still contains nutrients and seeds that were sown before the disturbance.

The homozygous genotypes' two alleles are not expressed over one another in incomplete dominance; instead, an intermediate heterozygote is created.

A significant contributing factor to the variety in the traits or properties of an organism is incomplete dominance.

Thus, Where a disturbance did not completely wipe out all life and nutrients from the environment, secondary succession occurs and homozygous.

Learn more about Secondary succession, refer to the link:

https://brainly.com/question/30229009

#SPJ2

The car is blue. What does that tell you about the light interacting with it?
A. Because the blue color wave is being reflected, and all other colors are being absorbed.
B. Because the blue color wave is being absorbed, and all the other colors are being reflected.
C. Because the blue color wave is being transmitted, and the others are not.

Answers

Answer:

A

Explanation:

because blue is being reflected, all other colors of light are being absorbed by the car.

Answer:

A: Because the blue color wave is being reflected, and all other colors are being absorbed.

Explanation:

Bright colors reflect light. Dark absorb. So white would reflect and black would absorb. Blue is bright, so it would reflect.

How would you get only brown offspring by breeding the mice you have?

Answers

When you put the gray mice offspring( first round). In the next round you take those mice from the first round and it will give you a brown offspring.

Cells that do not have a true nucleus are called.... *
1)eukaryote
2) prokaryote
3)unicellular
4) multicellular​

Answers

the answer is eukaryotic

Help Please!!
1- How could you tell whether a given sequence was DNA or mRNA?
2- Was it easier to decode messages written in DNA or in mRNA sequences?
3- Which cellular enzymes or machines are you imitating when you "transcribe" DNA into mRNA?
4- Which cellular enzymes or machines are you imitating when you "translate" mRNA into a chain of amino acids?
5- What else needs to happen in a eukaryotic cell between the processes of transcription and translation?
6- In step 5, how did different mutations affect the amino acid sequence that was encoded?
7- Explain why some single nucleotide mutations affect an amino acid sequence and some single nucleotide mutations do not.
8- Explain why nucleotide insertions and deletions affect the amino acid sequence so profoundly.
9- Why could your secret message include only 20 of the 26 letters of the alphabet?
10- Did you find that it was difficult to work with only these letters?

Answers

1. uracil (U) is dna and thymine T is mRNA
2 is an opinion
3 i think polymerases in rna

Answer:

DNA sequences use the nucleotides A, T, G, and C, while mRNA sequences use the nucleotides A, U, G, and C.

It was easier to decode the messages written in mRNA sequences because these sequences could be translated directly into the amino acid sequence.

The cellular enzyme that carries out transcription is RNA polymerase.

The cellular machine that carries out translation is the ribosome, which is composed of both rRNA and ribosomal proteins.

In a eukaryotic cell, an mRNA transcript often has additional untranslated regions and a poly-A tail. A eukaryotic mRNA transcript would need to be transported from the nucleus to the cytoplasm before it could be translated.

Some amino acids are encoded by several codons. If a single nucleotide mutation still encodes for the same amino acid, the resulting amino acid sequence would not be affected. This happens most often with nucleotides in the third position of a codon.

If a single nucleotide mutation changes the amino acid encoded, the resulting amino acid sequence would be affected. This happens most often with nucleotides in the first and second positions of a codon.

Nucleotide insertions and deletions cause frameshift mutations, which change the reading frame of translation and will encode completely different amino acids from that point forward.

There are only 20 canonical amino acids, so the letters B, J, O, U, X, and Z are not used as one-letter codes.

It was a little difficult to not use the letters B, J, O, U, X, and Z at first, but there are messages to write without these six letters.

Explanation:

alguien me podra ayudar en estas preguntas pls


2. ¿Será importante que usemos el suelo de manera sostenible?, ¿por qué?
Yo digo que sí, porque?

3- ¿Conocemos algunas técnicas de la agricultura ecológica? ¿Cuales?




4.- ¿Crees que estas técnicas agrícolas promueven el uso sostenible del suelo?, ¿por qué?





6.- ¿Qué problemática detectamos en el caso de los productores hortofrutícolas de la región Cajamarca?, ¿Por qué crees que necesario capacitar a los agricultores con respecto a esta problemática?


7.- ¿Qué métodos se están aplicando para enfrentar el problema?


8.- ¿Estás de acuerdo que el control químico en la erradicación de la mosca de la fruta debe ser empleado de manera responsable y solo en caso de ser indispensable?, ¿por qué?

Answers

Answer:

2. Si, porque de otra manera se producirían daños el medioambiente, deforestación, y degradación del suelo, el cual es un recurso no renovable.

3. Algunos ejemplos: Rotación de cultivos, mulching, abonos orgánicos o naturales, asociaciones de cultivos.

4. Si, porque no dañan el suelo.

6. La problemática se basa en un mal uso de los recursos hídricos, la falta de riego en los cultivos.

8. Si, porque como se mencionó anteriormente, un uso indiscriminado de químicos daña al medio ambiente.

Explanation:

La agricultura consiste en la práctica de cultivar plantas y criar ganado. Dicha técnica fue clave para el desarrollo de la civilización humana mediante la cual la cría de especies domesticadas y recolección de cultivos creó alimentos que permitieron a la gente vivir en ciudades. En el siglo XX, la agricultura industrial basada en el monocultivo a gran escala llegó a dominar la producción agrícola. En la agronomía moderna, el fitomejoramiento, el uso de los productos agroquímicos como los pesticidas y fertilizantes, y los desarrollos tecnológicos han aumentado considerablemente el rendimiento de las cosechas, al tiempo que han provocado daños ecológicos y medioambientales generalizados. Las prácticas modernas de cría de animales han aumentado la producción de carne, pero han suscitado preocupación por el bienestar de los animales y los daños medioambientales. Los problemas medioambientales incluyen la contribución al calentamiento global, el agotamiento de los acuíferos, la deforestación, la resistencia a los antibióticos y el uso de hormonas de crecimiento en la producción industrial de carne. Ejemplos de esta degradación del medio ambiente incluyen a la pérdida de biodiversidad, la desertificación, la degradación del suelo y el calentamiento global, que  a su vez provocan la disminución del rendimiento de las cosechas.

2. Si, porque de otra manera se producirían daños el medioambiente, deforestación, y degradación del suelo, el cual es un recurso no renovable. El uso sostenible del suelo permite conservarlo como recurso a largo plazo sin que se produzca su deterioramiento. Al no hacer uso sostenible del suelo, se pone el peligro la agricultura y a su vez la producción de alimentos. Hay que considerar que el suelo es un componente y recurso importante, un reservorio de gran parte de la biodiversidad del planeta. La vida de la flora y fauna depende del buen estado del suelo y nos resulta útil para la obtención de materia prima, siendo el área productiva del mismo limitada y bajo amenaza por los usos intensivos necesarios para satisfacer las demandas actuales. La gestión sostenible de los recursos del suelo contribuye eficazmente a prevenir el cambio climático.

3. Algunos ejemplos:

Rotación de cultivos: Consiste en la siembra sucesiva de distintos cultivos en un mismo terreno, a diferencia del monocultivo que se basa en la siembra repetida en el mismo campo. La rotación sirve para reducir la incidencia de plagas ya que se altera el ciclo de vida de los mismos, para controlar malas hierbas, para una distribución mas adecuada de nutrientes, etc.Mulching: Consiste en un método de corte en el cual la máquina cortacésped corta, se tritura, y se deja caer al suelo para que sirva como abono natural. Abonos orgánicos o naturales: Por ejemplo, estiércoles, compostas o residuos de cultivos. Permiten recuperar materia orgánica para la fijación de carbono, aumentan la actividad microbiana, favorece retención y uso de nutrientes y mejora la absorción de agua.Asociaciones de cultivos: Consiste en la siembra de dos o más especies próximas entre sí para que puedan beneficiarse la una de la otra.

4. Si, porque no dañan el suelo, no se utilizan compuestos artificiales o contaminantes y permite un crecimiento de la vegetación de forma mas natural, sin agotar sus recursos.

6. La problemática se basa en un mal uso de los recursos hídricos, la falta de riego en los cultivos. El riego consiste en brindarle agua a los cultivos para satisfacer sus necesidades hídricas que no fueron cubiertos mediante las lluvias, entonces es necesario capacitar a los agricultores para el correcto mantenimiento de los cultivos en cuanto a la proporción de agua que se les debe brindar.

8. Si, porque como se mencionó anteriormente, un uso indiscriminado de químicos daña al medio ambiente. Como así también disminuye la calidad de la fruta, afectando su sabor y sus nutrientes.

La mosca de la fruta es un insecto que produce un daño al picar el fruto, así las hembras realizan la ovoposición generando una vía de  entrada de hongos y bacterias que descomponen la pulpa de la fruta. Esto hace que se produzca una maduración precoz y caída del fruto, y la consiguiente pérdida de cosecha. Es necesario controlar esto pero de manera responsable.

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