when did anton van leeuwenhoek invent the microscope

Answers

Answer 1

Answer:

1666

Explanation:


Related Questions

where do daughter cells come from

Answers

Explanation:

Daughter cells are cells that result from the division of a single parent cell. They are produced by the division processes of mitosis and meiosis. Cell division is the reproductive mechanism whereby living organisms grow, develop, and produce offspring.

heparin is a naturally occuring anticoagulant produced by

Answers

Heparin is a naturally occurring glycosaminoglycan produced in the body by basophils and mast cells

how do potassium channels select the ion that can travel through the channel? group of answer choices membrane-spanning subunits concentration pore loop voltage

Answers

Answer:  Potassium channels allow K+ ions to easily diffuse through their pores while effectively preventing smaller Na+ ions from permeation. ... This selection process occurs at the narrow selectivity filter that contains structurally identified K+ binding-sites

Explanation:

When the Potassium channels allow K+ ions to easily diffuse through their pores while effectively preventing smaller Na+ ions from permeation. Although when This selection is processed occurs at the narrow selectivity filter that contains structurally identified K+ binding-sitesAfter that, The remarkable ability of the potassium channel to pass that is only potassium ions is accomplished by a selectivity filter at one end of the pore, as shown here from PDB entry 1k4c. when To pass through the selectivity filter, that is each potassium ion has to shed these water molecules.

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Someone please help me with this question

Answers

the appearance changes but the identity does not

in an otherwise normal cell, what happens if one mistake is made during dna replication?

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Answer:

Most mistakes are corrected, and if they are not, they may result in a mutation, defined as a permanent change in the DNA sequence. Mutations can be of many types, such as substitution, deletion, insertion, and trinucleotide repeat expansions. Mutations in repair genes may lead to serious consequences such as cancer.

Explanation:

Motor commands are carried by __________ from the brain along the spinal cord.

Answers

Answer:

descending tracts

Explanation:

Answer:

Descending tracts

Explanation:

"The descending tract is the pathway that the motor neurons take to reach the lower motor neurons that provide the nervous tissue needed for muscle movement."

Hope this Helps

which is true of the anterior horns of the spinal cord?

Answers

Answer:

They house cell bodies of somatic motor neurons.

Explanation:

each anterior root and corresponding posterior root unite within the intervertebral foramen to become a spinal nerve

How do differences between the peaks and valleys of the two graphs demonstrate interactions between these populations?

Answers

Answer:

peaks and valleys show population increase and decrease between 2 species or more.

Explanation:

the peaks and valleys are used to show predation hence if there is an increase in prey there will be an increase in the predators and if there is a decrease in prey there will be a decrease in predators therefore creating peaks and valleys in that graph hence demonstrating population interactions between the two species.

If a cell crossed over one time during Prophase I of Meiosis, how
many genetically distinct gametes would be produced?

Answers

Answer:

If crossing over doesn’t occur, then 2 out of the 4 daughter cells would be identical.

We have 46 chromosomes and are diploid meaning we got 1 set (23 chromosomes) from our mom and 1 set (23 chromosomes) from our dad.

In prophase 1, homologous chromosomes associate (chromosome #1 from dad and chromosome #1 from mom. They both code for the same things, but they are NOT identical)

Let’s compare mitosis to meiosis

On the left, see how in mitosis all chromosomes (even homologous) line up in single file (imagine all 46 lining up individually). When anaphase splits the sister chromatids (which are identical) in mitosis, each daughter cell gets the exact same genetic info.

(they get both homologous chromosomes: 1 from dad (yellow)and 1 from mom (purple) resulting in a full diploid set)

On the right in meiosis, see how the homologous chromosomes associate and will split? Chromosome #1 from mom (purple) is going to the left daughter cell while chromosome #1 from dad (yellow) is going to the right daughter cell. This means the two daughter cells will only have 1 set for chromosome #1 (either moms or dads but NOT both) and become haploid (1 set of 23 chromosomes)

Again in mitosis, all 46 lined up individually, but in meiosis the 23 from mom and 23 from dad first associate and each orient to decide which daughter cell gets the dads chromosome or the moms chromosome. They assort independently meaning just because dads chromosome #1 went to the left DOESN’T mean that dads chromosome #2 or #3 will go to the left. This gives a unique pattern of 23 chromosomes for the 2 daughter cells of meiosis 1 (a various mixture of moms and dads, but it is possible to result in a daughter cell with just moms and just dads set, though this would be a very small probability like 1 in 2^23 )

So each daughter cell of meiosis 1 is a haploid set (only 1 set instead of 2) and the opposite of the other (since 1 has fathers while the other has mothers for the same chromosome)

Meiosis 2 is just like mitosis. Here the sister chromatids separate producing 2 identical daughter cells

(identical if crossing over doesn’t occur. Crossing over only occurs on adjacent homologous chromatids)

If crossing over doesn’t occur then both sister chromatids are identical so that 2 out of 4 daughter cells will be exactly identical haploid sets. The other 2 are identical to each other as well.

Explanation:

Answer:

please give me brainlist and follow

Explanation:

Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. In contrast, meiosis gives rise to four unique daughter cells, each of which has half the number of chromosomes as the parent cell.

sorry .it's half answer

during which checkpoint would damaged or improperly replicated dna halt progression through the cell cycle?

Answers

Answer:

G2/Growth 2 phase

Answer:

When a cell's DNA is damaged, a sensor protein activates p53, which halts the cell cycle at the G 1start subscript, 1, end subscript checkpoint by triggering production of a cell-cycle inhibitor. This pause buys time for DNA repair, which also depends on p53, whose second job is to activate DNA repair enzymes.

Look at structure A Use the drop downs to answer the questions about this structure What is the name of this part of the flower What is the function of this part of the fower? A​

Answers

Answer:

What is the name of this part of the flower?

✔ sepal

What is the function of this part of the flower?

✔ to enclose the flower bud

Answer:the person above me is right.

Explanation:

Which of the following describe ways septic tanks potentially contaminate drinking water?

I. Using septic tanks in rural areas
II. Rising sea levels near coastline septic tanks
III. Leaks from septic tanks into groundwater

I and II
II and III
I and III
I, II, and III

Answers

Answer:

lll and ll

Explanation:

Answer:

| and ||

Explanation:

What is the biggest bird in the world?

Answers

Answer:

the biggest bird in the world is the Common ostrich

Explanation:

Brainliest ?

1. Which of the following is NOT a stress which affects plant cellular reactions?
A. Drought stress
B. Heat stress
C. Nutrient stress
D. Salt stress

Answers

Answer:

I believe the answer would be C. Nutrient stress. I hope this helps you! :)

What was the Court’s decision in United States v. Nixon (1974) and how did the decision uphold the idea that even the President of the United States is not above the nation’s laws?

Answers

Answer:

The Supreme Court decided that the President was required to turn over tape recordings and other materials that had been subpoenaed by special prosecutor Leon Jaworski.

In trying to withhold some materials related to the Watergate investigation, Nixon's lawyer had argued that the President of the United States "is not subject to the processes of any court in the land except the court of impeachment." The Supreme Court disagreed, in unanimous fashion. They held that the President could not use executive privilege as an excuse for hiding wrongdoing or avoiding prosecution. In an interview some years after his resignation, Nixon still held to his view, claiming that when the President does something, "that means that it is not illegal." He felt that being in the position of President put him above the law. But the Supreme Court had firmly disagreed. They rejected the idea of "absolute, unqualified Presidential privilege of immunity from judicial process under all circumstances." Executive privilege can only protect matters of military or diplomatic confidentiality

True or False: Exhalation is a passive process.

Answers

Answer:

true

Explanation: edg

Guys please help me this is my second time asking the same thinggg pls

How are coastal ecosystems a major source of oxygen for the rest of Earths waters?

Answers

Answer:

The ocean produces oxygen through the plants (phytoplankton, kelp, and algal plankton) that live in it.

Explanation:

These plants produce oxygen as a byproduct of photosynthesis, a process which converts carbon dioxide and sunlight into sugars the organism can use for energy. (hope this helps <3)

Lesson 3.01 (Page 1) talks about the different kids of ecosystem
succession.
If primary succession occurred would turtles be able to nest there?
What about secondary succession? (hint: what is the difference
between the 2?)

Answers

Answer:

In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area that was previously occupied by living things is disturbed, then re-colonized following the disturbance.

Explanation:

Hope this helps

how is carbon dioxide produced in a cenent plant

Answers

Carbon dioxide is emitted as a by-product of clinker production an intermediate product in cement manufacture, in which calcium carbonate (CaCO3) is calcinated and converted to lime (CaO), the primary component of cement. CO2 is also emitted during cement production by fossil fuel combustion.

Which muscle looks like a saw blade along the rib cage?

Answers

Answer:  Serratus anterior muscle.

Explanation:

6. The anterior muscles and tendons of the forearm do what action?

Answers

Answer:

The main action of pronator teres is pronation of the forearm at the proximal radioulnar joint, while it also contributes to the flexion of the forearm at the elbow joint. Start with the anatomy of anterior forearm muscles by exploring our videos, quizzes, labeled diagrams and articles.

If predators A and B prey upon the same species and predator A is eliminated, the population of predator B will likely __________.

a.
be eliminated
b.
increase
c.
decrease
d.
remain the same



Please select the best answer from the choices provided

Answers

Answer:

b

Explanation:

since predator seems to have the upper hand the predator a will most likey not be able to have any prey causing the preadotors b to inrease

Answer:

It's B

Explanation:

i think its its either C or D but i don't know correct me if I'm wrong.
A swimmer dives underwater and needs to swim a long distance while holding her breath. This prevents her body from getting oxygen.

What is most likely to occur in her cells so that glycolysis can continue to produce ATP?

a) cellular respiration
b) alcohol synthesis
c) lactic acid fermentation
d) alcohol fermentation

Answers

Answer:

C is the correct option.

Explanation:

Cells in the body continue to produce ATP in absence of oxygen.

Lactic acid fermentation is most likely to occur in the swimmer's cells so that the process of glycolysis can continue to produce ATP. Thus, the correct option is C.

What is Lactic acid fermentation?

Lactic acid fermentation is a metabolic process in which glucose or other six-carbon sugars are converted into cellular energy (ATP) and the metabolite lactic acid. It is an anaerobic fermentation reaction which occurs in some bacteria and animal cells, such as muscle cells and in absence of oxygen molecule.

Lactic acid fermentation happens in the skeletal muscles. In this process, pyruvate is converted to lactic acid by  the lactate dehydrogenase enzyme when oxygen is inadequate. Fatigue is brought on by the formation of lactic acid which buildup in the muscles.

Therefore, the correct option is C.

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If I don't give the Italians my third crowbar, will my pasta privileges be reviewed by an all knowing ferret?

Answers

Answer:

no

Explanation:

Answer:

yes

Explanation:

the Italians will be furious!! You will have no pasta and the ferret will scratch your face. PLEASE GIVE THEM YOUR CROWBAR! I BEG YOU! YOU DON'T WANT TO SEE THE ITALIANS ANGRY

Use the information to answer the following question.
1. tRNA brings the correct amino acid specified by the mRNA codon
2. DNA is used as a template to create mRNA, which leaves the nucleus
3. Amino acids are bonded together to make a polypeptide (protein)
4. mRNA molecule binds to a ribosome
5. The ribosome releases both the mRNA molecule and the polypeptide (protein)

Which of the following demonstrates the correct sequence of events that occurs during protein synthesis?

A. 2, 4, 1, 3, 5

B .2, 4, 3, 5, 1

C. 1, 2, 3, 4, 5

D. 4, 2, 1, 5, 3

Answers

Answer:

The correct sequence of events that occurs during protein synthesis? A

Explanation:

2. DNA is used as a template to create mRNA, which leaves the nucleus

4. mRNA molecule binds to a ribosome

1. tRNA brings the correct amino acid specified by the mRNA codon

3. Amino acids are bonded together to make a polypeptide (protein)

5. The ribosome releases both the mRNA molecule and the polypeptide (protein)

During protein synthesis, all the machinery for synthesis occurs in a sequential manner and the first need is a DNA template, so the correct option is a.

What events occur during protein synthesis?

Protein synthesis occurs in the ribosomal machinery and the process is called translation and starts after transcription.

DNA acts as a template for transcription and makes mRNA which translates into protein. mRNA act as a messenger for protein synthesis, this mRNA converts into protein with the help of ribosomal machinery.

In the process tRNA act as an adapter molecule adding an amino acid to the protein chain according to the codon on mRNA. In the last step protein and mRNA are released by the ribosome.

Therefore protein synthesis starts with DNA, hence option a is correct.

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what is the term that describes the deffusion of water through a selectivity permable membrane

Answers

Answer:

     

Explanation:

             

15. Which muscle is anterior to the tibia and helps prevent foot drop?

Answers

Answer: Anterior Tibialis muscle

Explanation:

double-stranded dna looks like a ladder that has been twisted into a helix, or spiral. the side supports of the ladder are:

Answers

Skskskskksksskkksksksakkskksakakwwkkkkkkoooollllllkkoko

which organ system is responsible for protection against injury, infection, and dehydration?

Answers

Answer:

The integumentary system protects the body's internal living tissues and organs, protects against invasion by infectious organism, and protects the.body from dehydration.

Explanation:

Most of the reactions by which energy from carbohydrates is released for use by the cell take place within the?

Answers

Answer:

Explanation:

The cellular process of releasing energy from food through a series of enzyme-controlled reactions is called respiration . Some of the energy released is used to produce ATP. Some of the energy released is lost as heat.

The release of energy from carbohydrates takes place within the

mitochondria.

The mitochondria is an organelle found within cells and it is regarded as

the power house of the cell. This is because energy is generated in it which

gives the cells power to perform its daily activities.

Energy generated from carbohydrate is usually in the form of ATP and it

involves series of reactions such as glycolysis, kreb cycle etc to ensure

adequate energy yield.

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