When does a zygote become an embryo?

once the embryo forms a heart, lungs, and brain
a few minutes after the male and female gamete fuse
once the zygote enters a safe environment either inside or outside of their mother
once the zygote starts dividing by mitosis and cell differentiation occurs

Answers

Answer 1

Answer:

Explanation:

The transformation of a zygote into an embryo adheres both to nature and to nurture: not only genetics but also environment determines the outcome. This idea has assumed many forms. A territory in the early sea urchin blastula contains clones of founder cells, and each clone contributes exclusively to one territory (Cameron & Davidson, 1991). Both the lineage of a founder cell, i.e. its nature, and the position of a founder cell, which determines how it is nurtured, contribute to its fate. Fertilisation, the topic of the first Forum, fixes the genes; interblastomere communication, the topic here, regulates gene expression. Blastomeres communicate like any other cell – via ligand-receptor interactions and through gap junctions. Saxe and DeHaan review these mechanisms. The definition of ligands and receptors becomes broadened in this context, and cell adhesions as well as gap junctions enter into the story. In spite of these entanglements, it appears that nature uses the same sorts of mechanisms to get cells to specialise that she uses to keep them talking. Thus, neurons and glial cells signal to one another via glutamate receptors and gap junctions (Nedergaard, 1994). Likewise, we expect neurotransmitters (and neurotransmitter transporters) to help signal differentiation. The biophysicist may ask whether electrical properties also play a role, but that we reserve for another Forum. If gap junctions figure in development as fusion pores that pass small molecules and electrical signals between blastomeres, another parallel suggests itself. Brian Dale asked in the first Forum: How does a spermatozoon activate an oocyte? This question, which concerns gamete communication, has produced two schools of thought and remains controversial (Shilling et al., 1994). Do sperm activate oocytes via contact-mediated mechanisms or through fusionmediated mechanisms? Or do both mechanisms occur, as they appear to in development?


Related Questions

What are the gonads in the male reproductive system.

Answers

Both men and women have gonads. In males, they are the testes, or testicles, the male s#x glands that are part of the male reproductive system. They are located behind the p#nis in a pouch of skin called the scrotum. The female gonads, the ovaries, are a pair of reproductive glands.

Bacteria in the _____ intestine produce vitamins, such as b and k.

Answers

Answer:

bacteria in the large intestine

How is seawater intrusion a negative impact to the ecosystem?.

Answers

Answer:

 Harm the availability or quality of source waters for drinking water utilities.

Explanation:

Compare the chromosome number of the parent cell with that of each daughter cell.

Answers

Answer:

In mitosis, the daughter cells have the same number of chromosomes as the parent cell, while in meiosis, the daughter cells have half the number of chromosomes as the parent.

Select the correct answer from each drop-down menu.
Analyze the pedigree shown.
O
square = male
circle female
expresses
trait
10- does not
10- carries trait
express trait
The tralt in the pedigree above is
wand
Reset

Answers

Answer:

Looks like a recessive trait, since both halves of the shape needs to be filled to make the trait active.

The pedigree is explained in the image, and the male is represented by the square and the female is represented by the circle. Here is the sex linked recessive pedigree present in the image.

What does the pedigree explain?

The pedigree explains the heritable pattern of traits, such as genetic diseases in males and females, as well as the chances of being diseased, such as with sex-linked recessive diseases, where males have a higher chance of being diseased than females. Here the image explains it is a sex-linked recessive disease because most females are carriers, which means they have a single copy of the recessive allele, but when they pass it on to their sons, they get fully diseased as they need a single recessive copy due to the presence of a single X chromosome.

Hence, the male is represented by the square, and the female is represented by the circle, and here is a sex linked recessive pedigree present in the image.  

Learn more about the pedigree here.

https://brainly.com/question/13667608

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Identifying an individual’s genetically influenced health risks could increase their potential to achieve optimal health. please select the best answer from the choices provided t f

Answers

It is a true statement that; "Identifying an individual’s genetically influenced health risks could increase their potential to achieve optimal health."

What are genetically influenced health risks?

Genetically influenced health risks are those healt risks that arise as a result of the genes inherited by an individual. These individuals may be predisposed to certain diseases due to their genotype.

Hence, it is a true statement that; "Identifying an individual’s genetically influenced health risks could increase their potential to achieve optimal health."

Learn more about health risks: https://brainly.com/question/12280232

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Assume all of the presynaptic synapses identified produce epsps. If two of these synapses fired simultaneously, which synaptic combination brings the initial segment closest to threshold based on spatial summation?.

Answers

The synapses that are nearer to the axon hillock would bring the initial segment closest to the threshold based on spatial summation.

What is neuron synapsis?

In neurosciences, the term synapsis makes reference to the connection between two nerve cells (neurons).

Synapsis is produced by the connection between axons and dendrites among different neurons.

Spatial summation refers to the start (trigger) of the action potential in neurons via two or more presynaptic cells.

Learn more about neuron synapsis here:

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Often, ____________ or basidiomycetes are the fungi involved, and they form several layers of hyphae, one of which envelops the photosynthetic ____________ .

Answers

Most of the time in lichen, ascomycetes or basidiomycetes form the fungal part with several hyphae layers enveloping the photosynthetic algal part.

Lichens

Lichens are composite organisms. They are formed from a symbiotic relationship between fungi and algae. The fungi provide shelter and some vital minerals for the algae while the algae provide food via photosynthesis.

Oftentimes, the fungi components are usually ascomycetes or basidiomycetes. They form a network of hyphae around the photosynthetic algae as a form of protection.

More on lichens can be found here: https://brainly.com/question/14040236

Are heated air and wind shear the cause for severe storms? Explain.

Answers

Answer:

Yes, they are very much the main cause of severe storms because the heat molecules get into the atmosphere and clouds, causing chemical reactions and damage. At some point in time, the energy built up, as well as the damage done, must undo itself. This is done through a storm. It is the environment's way of cleaning itself.

As a part from this video below states, wind shear is a leading cause in severe storms.

Absorption of glucose from the gut lumen depends on.

Answers

Answer:

protein and starch

Explanation:

the absorption depends on protein and starch

The black-footed ferret lives on the grasslands of North America. The species is endangered because of habitat loss and disease. What change would cause the species to become extinct?

A. Habitat loss continues to such an extent that the carrying capacity for black-footed ferrets becomes zero.
B. Disease continues to kill a constant percentage of all black-footed ferrets during the first year of life.
C. The black-footed ferret population decreases until the birthrate equals the death rate.
D. The black-footed ferret population decreases low enough for other limiting factors to affect it.

Answers

Answer: A is the answer

Refer to the diagram to answer the question. Which statement is true regarding how muscles contract?



Question 16 options:

Sarcomere A is contracted.


Sarcomere B is relaxed.


D represents Myosin.


C represents Myosin.

Answers

The figure is not found here, but myosin is the protein required for muscle contraction, whereas sarcomeres are functional units of muscles.

What is a sarcomere?

A sarcomere can be considered as the functional unit of a muscle, which is a type of contracting tissue.

A sarcomere is a unit composed of thick myosin fiber filaments and thin actin protein filaments.

These protein filaments work together to contract and expand sarcomeres and thus produce muscle movement.

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Which choice orders the average size of these star groups from smallest to largest?


Group of answer choices


A. White dwarf, red giant, main sequence


B. Red giant, main sequence, white dwarf


C. White dwarf, main sequence, red giant


D. Main sequence, white dwarf, red giant

Answers

Answer:

red giant , main sequence,white dwarf which is B

The image below shows three different types of cells.

Which correctly identifies each cell?

Answers

Answer:

B.

Explanation:

Cell A has a cell wall, Cell B has no cell wall, and Cell C has a fungal cell wall.

when is glycogen , which is stored in the liver , converted into glucose and released into the blood ?​

Answers

Answer:

This stored form of glucose is made up of many connected glucose molecules and is called glycogen. When the body needs a quick boost of energy or when the body isn't getting glucose from food, glycogen is broken down to release glucose into the bloodstream to be used as fuel for the cells.

How does the sun affect the movement of global winds
A. It causes global winds the curve.
B. It heats Earth's surface unevenly.
C. It heats the land and the water at the same rate.
D. It brings heavy rains in the summer.

Answers

Answer:

A is ur answer ur welcome hope this helps :) JACK

Explanation:

Part C
When only one color of light reflects from a piece of paper, what happens to the other colors of light? Remember that
light is energy, and energy cannot be created or destroyed.

Answers

Say that your paper is yellow, the color yellow is absorbed. The other colors? Reflected, mabey absorbed by another color object :D

write down the function of gynoecium

Answers

Answer:

The female reproductive organ of angiosperms, the gynoecium, often consists of the fusion of multiple ovule-bearing carpels. It serves the important function of producing and protecting ovules as well as mediating pollination.

Explanation:

Hope it helps(・∀・) Correct me if I'm wrong(๑•﹏•)

Which of the following is shown by this gel?
OA.
The size of various molecules or fragments of DNA.
ОВ.
The size of each individual DNA base.
OC.
The number of strands of DNA in a molecule.
OD.
The sequence of nucleotides in a molecule.

Answers

I believe it would be A. the size of the various molecules or fragments of DNA.

Energy in an ecosystem flows directly from _______. a. producers to tertiary consumers b. producers to secondary consumers c. tertiary consumers to secondary consumers d. secondary consumers to tertiary consumers please select the best answer from the choices provided a b c d

Answers

Answer:

A.

Explanation:

Primary producers use energy from the sun to produce their own food in the form of glucose, and then primary producers are eaten by primary consumers who are in turn eaten by secondary consumers, and so on, so that energy flows from one trophic level, or level of the food chain, to the next.

Energy in an ecosystem flows directly from producers to tertiary consumers. So, the correct option is A.

What do you mean by Ecosystem?

An Ecosystem may be defined as an area where organisms of different species are present together in a given time and interact with one another in order to survive.

In an ecosystem, producers produce the energy in the presence of sunlight through the process of photosynthesis. And then passes its energy to primary consumers (herbivores), then primary consumer passes their energy to secondary consumers (carnivores), then secondary consumers pass their energy to tertiary consumers. According to Lindeman, only 10% of energy get transferred to each trophic level.

Therefore, Energy in an ecosystem flows directly from producers to tertiary consumers.

To learn more about Energy flow between trophic levels, refer to the link:

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A cross between a yellow snake and a blue snake produces offspring that are all green. What type of inheritance is this?

Answers

Answer:

co dominance

Explanation:

codominance is a type of inheritance in which both allels are dominat over each other and the two allels are expressed to an equal degree in an offspring,that is why the cross between yellow and blue snake give another green colour offsprings in stead of giving all blue or all yellow offsprings depending on which allel is dominant.

as example we can take human blood group AB which is inherited from blood group A and B and both allel A and B are dominant over each other.

I hope it helped you!

How does carbon get from plants to animals like cows?

Answers

Answer:

Animals breath out Carbon and breath in Oxegon but plantes breath out Oxegon and breath in Carbon so a animal breath out the Carbon and the paint breaths that in and breaths out the Oxegon so the animal breaths the

Oxegon in

Hope This Helps :)

The right kidney sits ________ to the left kidney due to the position of the liver.

Answers

inferior

good luck on health!!

if both parents are heterozygous for a window's peak, what are the possible genotype and phenotypes of their children?​

Answers

Possible Genotypes: WW, Ww, ww

Possible Phenotypes: Has widow's peak or doesn't have widow's peak.

Which of the following stages is the first step during the process of transcription

Answers

Explanation:

RNA polymerase moves in the part of the DNA that has been opened and forms a complement to one of the strands of DNA called RNA.

List all the gametes that are possible with each of the following genotypes.
a. Aabb
d. AABb
b. AaBB
e. AAbb
C. AaBb
f. aabb

Answers

All the possible gametes for Aabb would be Ab and ab; that of AABb would be Ab and AB; that of AaBB would be AB and aB; that of AAbb would be Ab; that of AaBb would be AB, Ab, aB, and ab; and that of aabb would be ab respectively.

Gametes formation

The formation of gametes for a dihybrid involves the crossing of the two traits involved.

Thus: Aabb is equivalent to crossing Aa and bb

             

                           Aa   x   bb

                       Ab   Ab   ab   ab

Hence, all the gametes would be Ab or ab.

For AABb:                     AA   x   Bb  =   AB   Ab   AB   Ab

The gametes are either AB or Ab

For AaBB: the gametes are either AB or aB

For AAbb, only Ab gametes are produced

For AaBb: the gametes would be AB  Ab   aB and ab

For aabb: only ab gametes are produced.

More on gametes formation can be found here: https://brainly.com/question/931785

How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction?.

Answers

The non-competitive inhibitor will bind to the enzyme in a spot other than the active site. This means it does not necessarily block the active site but causes other changes in the enzyme that makes it unable to catalyze the reaction.

What happens when sunlight strikes a chlorophyll molecule?

Electrons in the mitochondria.
Electrons in the chlorophyll molecule become energized and move.
Electrons within the cell membrane become energized and move.
Electrons within the cell's nucleus are transferred to the chlorophyll molecule.

Answers

Answer:

Electrons in the chlorophyll molecule become energized and move

Explanation:

PLEASE MARK ME BRAINLIEST IF MY ANSWER IS CORRECT PLEASE

What makes a judas goat stop being social?

Answers

Answer:

anxiety

Explanation:

prokaryotic cells have nulcleus

Answers

Answer:

not nucleus, only nucleoid

Answer:

Prokaryotic cells are surrounded by a plasma membrane, but they have no internal membrane-bound organelles within their cytoplasm. The absence of a nucleus and other membrane-bound organelles differentiates prokaryotes from another class of organisms called eukaryotes.

Explanation:

hope it helps, God bless!

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