What is the structure of prokaryotic chromosomes

Answers

Answer 1

Answer:

1. Prokaryotic chromosomes are found in the nucleoid of prokaryotic cells, and they are circular in shape.

Unlike eukaryotic cells, prokaryotic cells don’t have a membrane-bound nucleus. Instead, their genetic material can be found in a region of the cytoplasm called the nucleoid. A prokaryotic cell typically has only a single, coiled, circular chromosome. However, there are a few prokaryotes that have more than one—Vibrio cholerae, the bacterium that causes cholera, has two circular chromosomes.

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Prokaryotic Chromosome

Prokaryotic cells typically have a single, circular chromosome located in the nucleoid.

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2. Each chromosome contains a molecule of DNA that is supercoiled and compacted by nucleoid-associated proteins (NAPs).

Prokaryotic cells may have only one chromosome, but that one chromosome is a very long DNA molecule that must be condensed to fit inside a tiny space. In a eukaryotic cell, DNA wraps around clusters of histone proteins. However, most prokaryotic cells don’t use histones to help with DNA storage. (Some Archaea do, but they are the exception, rather than the rule.)

Like eukaryotic DNA, prokaryotic DNA undergoes supercoiling, but it is not wound around histone clusters first. Supercoiling uses the application of tension to twist a DNA molecule, so it wraps around itself, creating loops.

The folding of prokaryotic DNA is facilitated by nucleoid-associated proteins (NAPs) instead of histones. NAPs are proteins within the nucleoid that can bind to the DNA molecule, introducing bends and folds, and they are involved with processes such as DNA replication and transcription.

3. Prokaryotic cells are haploid, meaning they do not have chromosomes that occur in homologous pairs.

Most prokaryotic cells have just one chromosome, so they are classified as haploid cells (1n, without paired chromosomes). Even in Vibrio cholerae, which has two chromosomes, the chromosomes are unique from one another. That is, they are not a homologous pair, because they don’t contain the same genes in the same locations.

Many prokaryotes, such as bacteria, reproduce via binary fission. This is a method of asexual reproduction that is similar in its end result to mitosis—two daughter cells result, each with the same number of chromosomes as the parent cell. However, when bacteria undergo binary fission, no mitotic spindle forms. In addition, the replication of the prokaryotic cell’s chromosome can occur during the fission process.

4. Prokaryotic cells can also carry small molecules of DNA called plasmids.

Plasmids are small, circular DNA molecules that contain the cell’s nonessential genes. Although plasmids can occur in a variety of sizes (ranging from around a thousand base pairs to hundreds of thousands), they usually only have a small number of genes. Antibiotic resistance is a trait that is frequently attributed to genes on plasmids.

In addition to their single chromosome, prokaryotic cells often have small, circular DNA molecules called plasmids.

The genetic material of plasmids is separate from that of the cell’s main chromosome, and they can replicate independently of that chromosome. When a prokaryotic cell with a plasmid divides, the daughter cells each receive a copy of the plasmid, along with its regular chromosome.

5. Prokaryotic and eukaryotic chromosomes differ in their shape, size, number, and location within the cell.

Here’s how the characteristics of eukaryotic and prokaryotic chromosomes compare.

 Eukaryotic Chromosome Prokaryotic Chromosome

Shape Linear Circular

Size Large Small

Number Multiple Single

Location Nucleus Nucleoid (region in cytoplasm)

Storage proteins Histones Nucleoid-associated proteins

Visible Body Biology

 

 External Sources

“The Precarious Prokaryotic Chromosome” from the Journal of Bacteriology.

A video on DNA topology and supercoiling from the MITx Molecular Biology course.

“Nucleoid Associated Proteins: The Small Organizers That Help to Cope With Stress” from Frontiers in Microbiology.

An article from Scitable/Nature Education on genome packaging in prokaryotes.

An article from Khan Academy about binary fission in bacteria.

“The Vibrio cholerae genome contains two unique circular chromosomes,” from the Proceedings of the National Academy of Sciences.

Definitions of plasmids from Scitable and the National Human Genome Research Institute.

Related Articles

Explanation:

Prokaryotic chromosomes are found in the nucleoid of prokaryotic cells, and they are circular in shape.


Related Questions

8)
Carbon dioxide is removed from the atmosphere by
A)
the burning of forests
B)
the burning of fossil fuels
C)
respiration
D)
photosynthesis

Answers

D) Photosynthesis

Explanation:
Plants use Carbon dioxide in the process that turns sunlight, carbon dioxide and water into glucose and oxygen
D) Photosynthesis.

The reason why it’s D is because photosynthesis removes carbon dioxide naturally — and trees are especially good at storing carbon removed from the atmosphere by photosynthesis.

Toby and his brother Jedidiah are eating burgers. All of a
sudden, Jedidiah begins to gasp for air, grabs his neck, and
starts turning blue in the face. What can Toby do to help
Jedidiah?

A.perform CPR
B. give him an inhaler
C. perform the heimlich maneuver
D.nothing, it will pass

Answers

Answer :
Perform Heimlich maneuver

Is it normal for a period to not come on for 1 month im worrying ​

Answers

Answer: It depends. Your period might sometimes come some days later or earlier because of stress or another thing. It should be fine if it comes one or two days after the date it is supposed to come, if not, well, you might be pregnant or some health problem that has delayed it.

A plant's water supply is now deeper in the ground.
What process allows the roots to grow longer?

A. interphase


B. photosynthesis


C. mitosis


D. meiosis

Answers

The answer is c.mitosis

A 75 kg patient needs a medication X in the amount of 0.2 mg/kg/day. The medication comes in a liquid solution of 50 mg for every 1000 ml. How many ml of this solution will this patient need in a day? If this solution is being infused at 60 ml/hr, how long with the transfusion take?

Answers

Answer:umm.....

Explanation:

Meteorologists refer to the water vapor in the atmosphere as

Answers

Answer:

^^ The answer is below ^^

Explanation:

Water vapor is water in the gaseous phase. Meteorologists have defined several different terms to express the amount of water vapor in air. ... Specific humidity is the ratio of the mass of water vapor in a sample to the total mass of the moist air, including both the dry air and the water vapor.

Meteorologists refer to the water vapour in the atmosphere as moisture or humidity.

What are water vapours?

The atmosphere is continually being circulated with water. Water evaporating from the surface of the Earth rises into the sky on heated updrafts. When the air is driven by the wind, it condenses into clouds before returning to Earth as rain or snow. This cycle is vital to how heat and energy are moved around our globe from one location to another and from the Earth's surface to the atmosphere.

The most significant greenhouse gas found in the atmosphere is also water vapour. The heat emitted from the surface of the Earth is absorbed by water vapour molecules in the lower atmosphere. In turn, the molecules of water vapour emit heat in all dimensions. The Earth's surface receives some of the heat back. So, in addition to sunshine, water vapour serves as a second source of warming for the Earth's surface.

Therefore, meteorologists refer to the water vapour in the atmosphere as moisture or humidity.

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Which part of the flower accepts the pollen

Answers

Answer:

the part which allows the pollen is the stigma

Interview 10 different people
Ask:
–Which city they live in. Must be different cities.

–If the person recycles

–If they recycle – what? (paper, plastic, metal, etc.)

–How they recycle – home bin, recycling center, etc.

–If NOT – why? What would encourage recycling?

Answers

Answer:

ok

Explanation:tahy all were like why

I’m one person
I live in NYC
I recycle by leaving glass bottles, plastic bottles and cardboard in a different place.
I put recyclables in the recycling compartments.
Hope this helps

Why do scientists organize living things into groups?

Answers

Explanation:

Biologists use classification to organize living things into groups so that organisms are easier to study. ... Speicies with similar evolutionary histories are classified more closely together.

Answer:

Biologists use classification to organize living things into groups so that organisms are easier to study. ... Speicies with similar evolutionary histories are classified more closely together.

Explanation:

What is the main reason why the climate is changing?
(I NEED THIS ASAP)

Answers

Answer:

green house gasses

Explanation:

the increase of gasses in the atmosphere has caused the temp. to rise

Answer:

Explanation:

The main reason why the climate is changing because we use a lot of fossil fuel and pollution and cutting down trees and rainforests. Also, this adds enormous amounts of greenhouse gases to those naturally occurring in the atmosphere, increasing the greenhouse effect and global warming.

Photosynthesis results in *
An oxygen-rich atmosphere
Glucose, a food for plants
Glucose, the source of energy for all living things on earth
All of the above
What will happen to the rate of photosynthesis, if the temperature is

Answers

The answer is “all the above” :)

WILL MARK BRAINLIEST WORTH 20 POINTS

Which of the following limit cell size? Select all of the answers that apply.
A. ratio of surface area to volume
B. rate of moving materials across the cell's membrane
C. efficiency of using the information in a cell's DNA
D. efficiency of DNA replication and cell division

Answers

Answer:

Okrtyuiop[poiuytfdfghjkl;lkjhgfcvbnm,

Explanation:

two____ cells are created through mitosis. 100 POINTS!!!
0 sperm

0 identical

0 different

Answers

Answer:

The answer is identical.

Explanation:

Mitosis is a nuclear division giving rise to a genetically identical cells.

Answer:

identical

Explanation:

mitosis forms daughter cells, the copy of identical chromosomes

In order to maintain a high level of performance, what types of foods do you think an athlete should eat right before a race? Select one.

Answers

Answer:

According to me it's energy bars and fruits, but u can give ur own opinion.

How are solids, liquids, and gases different?

Answers

Answer:

Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the behaviors of these particles differ in the three phases.

Explanation:

gas are well separated with no regular arrangement. liquid are close together with no regular arrangement. solid are tightly packed, usually in a regular pattern.

Which action is the best way to turn an electromagnet off?

Answers

Answer: 1) The strength of the electromagnet increases   →   Place a magnetic core inside the coil of wire

2) The electromagnet turns off    →    Turn off the battery supply

3) The poles of the electromagnet reverse     →    Change the direction in which the current flows

Explanation:

when current passes through a coil it behaves a an electromagnet.

Magnetic field strength is given by

B = μ N I  

N is no of turns and

I is the current through coil

μ is permeability of the medium or core in the coil.

1). Magnetic core increase permeability μ so it will strengthen magnetic field:

B = μ N I

2). When the battery turns off current becomes zeroi.e I=0

So B = μ N * 0

⇒ B = 0

so electromagnet turns off

3). Direction of magnetic field can be determine by right hand rule, i.e curl the fingers in the direction of current, thumb will point in the direction of north pole.

so changing current direction will change direction of magnetic field.

Explain the role the ocean plays in the carbon cycle (think about the physical and biological processes that occur in the ocean)

Answers

Answer:

i need help with this exact question.

Explanation:

which group contains only molecules that are each assembled from smaller organic compounds

Answers

Proteins, DNA, fats, starch

What is a clue that the lac operon is on?

A.)Lactose is absent.

B.)The cell membrane changes.

C.)The repressor protein has fallen off the molecule.

D.)RNA polymerase is blocked by the repressor.

Answers

The correct answer is C.) The repressor protein has fallen off the molecule.

The lac operon is a regulatory system found in bacteria, which controls the expression of genes involved in lactose metabolism.

The lac operon consists of three main components: the structural genes (lacZ, lacY, and lacA), the promoter region, and the operator region. The regulation of the lac operon depends on the presence or absence of lactose and glucose.

In the absence of lactose, the lac repressor protein binds to the operator region of the operon, preventing the expression of the structural genes. This inhibits the production of enzymes involved in lactose metabolism.

However, when lactose is present in the environment, it acts as an inducer. Lactose is converted into allolactose, which binds to the repressor protein and causes it to undergo a conformational change. As a result, the repressor protein falls off the operator, allowing RNA polymerase to bind to the promoter region and transcribe the structural genes.

Therefore, the clue that the lac operon is on is the falling off of the repressor protein from the operator region, enabling gene expression and the production of enzymes required for lactose metabolism. Therefore, the correct answer is C.

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Why do different colors affect photosynthesis differently

Answers

Answer:

Plants do respond differently to different colors of light being shone on them, because chlorophyll reflects green light and absorbs blue and red (therefore, blue and red are useful for photosynthesis, but green isn't).

Explanation:

Explain how a moderate
increase in (1) light and (2) carbon dioxide could
affect photosynthesis in a desert plant. Address
both conditions for full credit.

Answers

Answer:

1) Moderate increase in light increases the photosynthetic rate

2) Moderate increase in CO2 increases the photosynthetic rate

Explanation:

Photosynthesis is a metabolic process unique to the cells of autotrophic organisms such as green plants. It is the process whereby they synthesize their food in form of sugars (glucose) in the presence of sunlight energy.

The photosynthetic process, although comprises of several reactions and processes, is generally described as the reaction of carbon dioxide, water and light to give glucose and oxygen gas as products. The general equation is as follows:

6CO2 + 6H2O + light → C6H12O6 + 6O2

Since both light (needed to supply energy) and CO2 (carbon source) are reactants of the photosynthetic process, a MODERATE INCREASE in them will INCREASE THE RATE AT WHICH PHOTOSYNTHESIS OCCURS.

Cells that are carrying out normal day to day fuctions are in which phase of the cell cycle?
Answer Choices
A .Cytokinesis
B. Mitosis
C. Interphase

Answers

Answer:

i think its B. Dont take my word for it tho..

Explanation:

sorry if its wrong :'(

Answer:

mitosis

Explanation:

Will give brainlest and a heart if correct

Answers

Answer:

A

Explanation:

i have done the test

The answer is A hoped this helped

Is water and its properties important in homeostasis for humans ? explain.

Answers

Answer:

yes its important because...

Explanation:

Water is an essential feature of homeostasis in an organism. Water increases the volume of blood, which affects blood pressure and heart rate. Water dissolves gases and allow for efficient exchange and transport of oxygen and carbon dioxide. Water can be excreted, so it carries toxins that have been made water-soluble out of the body.

please help me plz :(

Answers

Answer:

They're Multiplying

Explanation:

Im ony GUESSING here but it looks like they are multiplying

they’re multiplying rapidly, which is what causes cancers(rapid cell growth)

At which ocean-floor feature do plates move together?

Answers

Answer:

divergent plate boundaries

Explanation:

Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense.

What's a quote in the poem "two kinds" that encouraging

Answers

"So maybe I never really gave myself a fair chance. I did pick up the basics pretty easily, and I might have become a good pianist at that young age. But I was so determined not to try, not to be anybody different that I learned to play only the most ear-splitting preludes, the most discordant hymns"

this is a quote you can use from the book “two kinds” by amy tan that could be considered “encouraging”!

hope this helps :)

If you see a lamp that doesn’t look like a lamp to you, but it expands your idea of what a lamp is, you are experiencing:
A) image formation
B) mental concepts
C) concept expansion
D) concept formation

Answers

If you see a lamp that doesn’t look like a lamp to you, but it expands your idea of what a lamp is, then you are experiencing the idea of concept formation (Option D).

What is the concept formation?

The concept formation is a cognitive process in which the info is perceived by the senses and then this data is held in the memory.

In conclusion, if you see a lamp that doesn’t look like a lamp to you, but it expands your idea of what a lamp is, then you are experiencing concept formation (Option D).

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Explain why it is important to be skeptical of statistical results reported in the media.

Answers

Answer:

Firstly, many statistics are taken from a small group of people used to represent the general population. Say a news channel reported that 81% of teenagers in America were planning on going to a four-year college. This statistic is most likely taken from a randomly selected group of teenagers, and calculated with a margin of error. Because after all, it's nearly impossible to survey every single teenager in America. This can lead to some statistics that are not really representative of the actual percentage of people. This only gets more likely the larger the general population being "surveyed" is. Another reason is that the media is not always truthful with statistics. Things can be altered and not many people will notice. Hope this helps!

The gene frequency for a particular trait in a population was determined to be 80% A (dominant allele) and 20% a (recessive allele). Fifty years later, the gene frequency was determined to be 60% A and 40% a. What does this change most likely indicate about the gene pool?

Answers

Answer:

Explanation:

Microevolution is a change in the frequency of gene variants, alleles, in a population, typically occurring over a relatively short time period.

Population genetics is the field of biology that studies allele frequencies in populations and how they change over time.

Allele frequency refers to how common an allele is in a population. It is determined by counting how many times the allele appears in the population then dividing by the total number of copies of the gene.

\text{Frequency of allele }AFrequency of allele Astart text, F, r, e, q, u, e, n, c, y, space, o, f, space, a, l, l, e, l, e, space, end text, A ==equals \dfrac{{\text{Number of copies of allele }A \:{\text {in population}}}}{\text{Total number of }{\text{copies of gene in population}}}  

Total number of copies of gene in population

Number of copies of allele Ain population

​  

start fraction, start text, N, u, m, b, e, r, space, o, f, space, c, o, p, i, e, s, space, o, f, space, a, l, l, e, l, e, space, end text, A, start text, i, n, space, p, o, p, u, l, a, t, i, o, n, end text, divided by, start text, T, o, t, a, l, space, n, u, m, b, e, r, space, o, f, space, end text, start text, c, o, p, i, e, s, space, o, f, space, g, e, n, e, space, i, n, space, p, o, p, u, l, a, t, i, o, n, end text, end fraction

The gene pool of a population consists of all the copies of all the genes in that population.

This change in the gene pool most likely indicates the existence of microevolution. It generally includes the implications of various evolutionary forces like migration, genetic drift, mutation, natural selection, etc.

What is Microevolution?

Microevolution may be characterized as a series or sequence of changes that may lead to alterations in the frequency of genes. Due to this, the overall gene pool may get influenced within a particular time.

This methodology and the complete process of alteration in the gene pool with respect to the evolutionary forces are studied under population genetics. It is the field of biology that significantly involves the detailed study of alleles and their frequencies among populations.

According to the context of this question, the gene frequency for a particular trait in a population was determined to be 80% A (dominant allele) and 20% a (recessive allele). Fifty years later, the gene frequency was determined to be 60% A and 40% a. This is due to the microevolution.

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