what must happen before crossing over can occur in meiosis
Answer:
Crossing over occurs between prophase I and metaphase I and is the process where two homologous chromosome non-sister chromatids pair up with each other and exchange different segments of genetic material to form two recombinant chromosome sister chromatids.
Before crossing over can occur in meiosis, homologous chromosomes must line up during prophase I, and DNA replication must have taken place to form sister chromatids. Crossing over involves precise DNA exchanges between non-sister chromatids, and is critical for genetic diversity and integrity.
Before crossing over can occur in meiosis, several steps must take place. Firstly, during prophase I, the homologous chromosomes line up together. This alignment is crucial because it sets the stage for the exchange of DNA between these paired chromosomes. Before the exchange, the DNA must be replicated to form sister chromatids, and the chromosomes condense and coil up tightly. During prophase I, crossing over occurs when a double strand break on one DNA molecule is joined with a double strand break on another, allowing the exchange of genetic material between non-sister chromatids, typically at the same relative locations.
The accuracy of crossing over is vital for maintaining genetic integrity, as it must be done with precision to prevent the gain or loss of genes. Any inaccuracy, such as a frameshift mutation, could result in a defective gene product or no product at all. Crossing over not only assists in holding the chromosomes together until they separate in anaphase I, but it also facilitates genetic recombination between linked genes. After crossing over, during metaphase I, the homologous chromosomes randomly assort on the metaphase plate, further contributing to the unique genetic makeup of the resulting gametes.
How do the three types of RNA work together at a ribosome to synthetize
A polypeptide?
Answer:
Explanation:
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and DNA are nucleic acids, and, along with lipids, proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single strand folded onto itself, rather than a paired double strand. Cellular organisms use messenger RNA (mRNA) to convey genetic information (using the nitrogenous bases of guanine, uracil, adenine, and cytosine, denoted by the letters G, U, A, and C) that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome.
tRNA, is found in the cytoplasm and is involved in protein synthesis. Transfer RNA transports amino acids to the ribosome, one for each three-nucleotide codon of rRNA. The amino acids can then be combined and processed to form polypeptides and proteins. The template for this is formed by mRNA.
What is a polypeptide?A polypeptide is an unbranched chain of amino acids connected by peptide bonds.
mRNA is the one that make template for protein synthesis. tRNA is a protein synthesis enzyme found in the cytoplasm.
Transfer RNA, one for each three-nucleotide codon of rRNA, transports amino acids to the ribosome. After that, the amino acids can be combined and processed to create polypeptides and proteins.
Thus, in this way the three RNA works together to form a polypeptide.
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capillary action is the ability of water to travel up narrow tubes. true or false
Answer:
true
Explanation:
Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus which turns upward. The surface tension acts to hold the surface intact. Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules.
Examine the scenario.
Chemical Reaction A and Chemical Reaction B involve the same two reactants. Chemical Reaction A is performed in a hot container, while Chemical Reaction B is performed in a cold container.
Which of the answer choices correctly describes which chemical reaction will have a higher reaction rate?
1)Chemical Reaction A will have a higher reaction rate, because its container has more thermal energy. This thermal energy will cause the reactants' particles to divide and take on a smaller surface area.
2)Chemical Reaction B will have a higher reaction rate, because its container has less thermal energy. This thermal energy will cause an increase in the motion and collisions of the reactants' particles.
3)Chemical Reaction B will have a higher reaction rate, because its container has less thermal energy. This thermal energy will cause the reactants' particle to divide and take on a smaller surface area.
4)Chemical Reaction A will have a higher reaction rate, because its container has more thermal energy. This thermal energy will cause an increase in the motion and collisions of the reactants' particles.
Answer: D) Chemical Reaction A will have a higher reaction rate because its container has more thermal energy. This thermal energy will cause an increase in the motion and collisions of the reactants' particles.
More heat = more reaction
Explanation: took the test got it right.
Chemical Reaction A, performed in a hot container, will have a higher reaction rate due to more thermal energy increasing reactants' particle motion and collision frequency, making reactions more likely to occur. Hence, the correct option is 4.
When considering Chemical Reaction A in a hot container and Chemical Reaction B in a cold container, using identical reactants, the reaction in the hot container (Chemical Reaction A) will have a higher reaction rate. This is because the increased thermal energy in Chemical Reaction A causes the reactants' particles to move more rapidly, resulting in a higher frequency of collisions and increasing the likelihood of these collisions being effective enough to surpass the activation energy barrier and form products. Therefore, among the given options, the correct description is:4)Chemical Reaction A will have a higher reaction rate because its container has more thermal energy. This thermal energy will cause an increase in the motion and collisions of the reactants' particles.
What enzymes make up pancreatic juice? What does each enzyme do to help digestion?
Answer:
The following enzymes make up the Pancreatic Juice
1. Trypsinogen
2. Chymotrypsinogen
3. Elastase
4. Carboxypeptidase
5. Pancreatic Lipase
6. Nucleases
7. Amylase
Explanation:
1. Trypsinogen helps in Protein Digestion.
2. Chymotrypsinogen is also used in the small intestine to break down proteins into individual amino acids, but it specifically targets the aromatic amino acids, tyrosine, phenylalanine, and tryptophan.
3. Elastase cleaves the peptide bonds in elastin, aiding in its digestion.
4. Carboxypeptidase breaks down the first peptide or amide bond at the carboxyl/C-terminal end of proteins and peptides.
5. Pancreatic Lipase is a primary enzyme that breaks down dietary fat in the digestive system.
6. Nucleases are responsible for breaking the bonds between nucleotides in nucleic acids.
7. Amylase catalyze the splitting of starch into smaller carbohydrate molecules such as maltose (two glucose molecules) by addition of water molecule.
Savannah wraps some gifts and then brings them to the post office where
they are delivered to people in different parts of the country. Which
organelle is Savannah most like?
Golgi body
cell membrane
lysosome
chloroplast
Need ASAP
Answer:
Savannah is acting as the golgi body.The golgi body is responsible for shipping nutrients around the cell to keep it functioning well
hope this helps....mark me the brainliest plzz
Answer:
Savannah wraps some gifts and then brings them to the post office where
they are delivered to people in different parts of the country. Which
organelle is Savannah most like?
Golgi body plays such vital role that Savannnah plays in the above description
Explanation:
Golgi body entails putting together of protein before they are distributed to where needed.
A student performed an experiment to test the
acidity of foods. Put the following steps in the order
they should occur.
The student
records the acidity of the food.
asks a question about food's acidity.
observes that there are acidic foods.
presents the results to the class.
prepares to conduct the experiment.
creates a hypothesis about the acidity.
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The steps of scientific method to be used are as follows:
Observes that there are acidic foods.
Asks a question about food's acidity.
Creates a hypothesis about the acidity.
Records the acidity of the food.
Observes that there are acidic foods.
Presents the results to the class.
Explanation:
The scientific method or problem solving approach or experiment to be conducted involves five necessary steps these are:
1. Make an observation: that there are acidic foods.
2. Ask a question to yourself: a question about food's acidity.
3. A hypothesis to be made or proposed: A hypothesis or an explanation for the acidity of food is made.
4. Predictions are made: acidity in the food source is recorded.
5. Testing of prediction or hypothesis is done: food samples tested and found that acid is present in them.
6. Iterate: If the result does not support the hypothesis made, new hypothesis is to be designed and if the result came as expected the hypothesis gets excepted and experiment is performed.
discuss how biodiversity the increase and decline of the elephant population
Biodiversity can be impacted by the increase or decline of the elephant population. This can result in either a decrease or disruption of biodiversity in the ecosystem.
Explanation:The Impact of Biodiversity on Elephant PopulationBiodiversity refers to the variety of life forms in an ecosystem, including different species and their genetic variations. The increase or decline of the elephant population can have significant effects on biodiversity.
Increase of Elephant Population:If the elephant population increases, it could lead to a decrease in biodiversity in the ecosystem. Elephants are mega herbivores that require large amounts of food and space. As their population grows, they may overgraze or trample vegetation, leading to decreased species diversity and habitat loss for other organisms.
Decline of Elephant Population:On the other hand, a decline in the elephant population can also negatively impact biodiversity. Elephants play a crucial role in ecosystem dynamics through their feeding habits and seed dispersal. When elephant numbers decline, it can disrupt plant communities and reduce the availability of food and resources for other species, leading to a decrease in biodiversity.
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Elephant populations increase in African nations with property rights and stable political systems, but decline due to poaching and habitat loss, despite the international ivory trade ban.
The relationship between biodiversity and elephant populations is multifaceted, demonstrating both how measures to protect these animals can lead to their population increase and how various threats contribute to their decline. An analysis by Professors McPherson and Nieswiadomy illustrated that elephant populations have increased in African nations with established property rights and stable political systems, which can include exclusive, transferable licenses to hunt elephants. Nations like Botswana and Zimbabwe are examples where such practices have led to significant rises in elephant numbers.
Conversely, in cases where these conditions are not met, and especially with the impact of human activities such as poaching and habitat encroachment, elephant populations are in decline. Forest elephants, even in isolated national parks, have suffered from poaching and range reduction despite international agreements like CITES, which banned the trade in ivory. The challenges also include ethical debates over culling, effects on habitats, and conflicts with human interests, which all play a role in the conservation and management of elephant populations.
A human living now and a horse that lived thousands of years ago could:
O A. get their energy directly from the Sun.
O B. have some of the same DNA molecules.
O C. be made of some of the same matter
O D. use the same amount of energy to survive,
Answer:
C. be made of some of the same matter
Explanation:
The human beings living in the present time can be related to the horses that lived thousands of years ago.
This could be due to the fact that resources on the Earth were present in the past had been recycled again and again through the biogeochemical cycles.
This shows that the elements present on the Earth can be reused again and again and the elements which could have composed the horse now form the matter in the humans.
Thus, Option-C is correct.
Tropical storms and hurricanes are weather patterns formed in the Atlantic Ocean. Name the same weather pattern that travels across the Pacific Ocean
A. cyclone
B. tsunami
PLEASE HELP!!!!!!!
Answer:
A)Cyclone
Explanation:
PLZ HELP What would happen if a cell dissolved in water like sugar does
Answer:
Okay I don’t really think anything would happen to the cell part from maybe it could be affected physically if it’s physical maybe it it could get brighter or smaller or nothing at all. It depends what cell it is.
7. Structure X would be involved in the
(1) storage of digestive enzymes
(2) absorption of energy from the Sun
(3) development of pathogens
(4) synthesis of proteins
Answer:
4
Explanation:
Why doesn't the original grass remain the dominant plant on the sand dune
Answer:
NEW PLANTS ARE BETTER SUITED TO THE NEW CONDITIONS IN THE SAND DUNE HABITAT
Explanation:
17. Which of the following actions by humans adds the greatest amount of carbon dioxide to
the atmosphere?
A cultivating new breeds of plants
C burning coal for electricity
B using solar powered calculators
D planting grass in neighborhoods
Answer:
C. Burning coal for electricity.
Explanation:
When fuels like wood, coal petroleum and natural gas are burnt, the carbon in them is oxidized to carbon dioxide which returns to the atmosphere. Coal, petroleum and natural gases are known as fossil fuels. Coal comes from the partly decayed remains of ancient plants that became buried millions of years ago and were subjected to great pressure. As these fossil fuels take time millions of years to form, the carbon in them tends to recycle very slowly. In as much as they take time to form, they are been used up rapidly.
What is the image obtained by plotting dots, bars or lines to show scientific data
Answer:
it is a graph
Explanation:
A graph is the visual representation, achieved by plotting dots, bars, or lines, which represents scientific data. These can be line graphs, bar graphs, or scatter plots, each used for different purposes.
Explanation:The image obtained by plotting dots, bars, or lines to show scientific data is called a graph. Graphs are a visual representation of data, which help to understand the information in a much easier and quicker way than looking at raw numbers. There are several types of graphs like line graphs, bar graphs, and scatter plots. For instance, a line graph is used to demonstrate a change over time, a bar graph is used to compare different items, and a scatter plot is used to show the relationship between two variables.
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What does it mean if somebody has a lump under their testes?
A.) AIDS
B.) Herpes
C.) Cancer
D.) Ghonnaherpasyphillis
Which effect can an ocean have on the climate
Answer:
Tempature
Explanation:
The ocean cools and heats up slower then land so let's take NY in the US for an example a city in upstate NY is not near a body of water so the tempatures will be much hotter in the summer and colder in the winter now let's take NYC one of the biggest cities in the world it's on the coast and in the winter the water stores heat making the winter a littler warmer then upstate and the summers a little cooler then upstate
How many nitrogen bases are needed to specify 4 amino acids? a. 3 b. 6 c. 9 d. 12
Answer: Option D is correct (12).
Explanation:
Codon is a set of DNA or RNA nucleotides so each amino acids are coded by 3 bases. For the specification of 4 amino acids, 12 bases are required. 3*4=12
The continental United States is closer to the equator than Canada is. Based on this information, we'd expect the continental U.S. to have a _____ climate than Canada.
A. drier
B. hotter
C. colder
D. wetter
The interaction between the hummingbird and the orchid flowers is mutualistic in nature. Hummingbirds benefit by getting nectar from the flowers. How would the flowers benefit in return?
Answer:
The flower is pollinated
Explanation:
The mutualistic relationship between hummingbirds and orchid flowers primarily benefits the flowers through pollination, which aids in their reproductive process. Option B is correct.
This means that both parties benefit from the interaction. While the hummingbirds gain energy-rich nectar from the flowers, the flowers benefit through pollination. As the hummingbirds feed on the nectar, they inadvertently transfer pollen from one flower to another, facilitating the flowers' reproductive process.
Pollination: The primary benefit is that the flowers get pollinated. The hummingbirds carry pollen on their heads and necks, transferring it to other flowers they visit.Reproduction: This pollination process is essential for the flowers' reproduction, helping to produce seeds for the next generation of plants.Complete question as follows:
The interaction between the hummingbird and the orchid flowers is mutualistic in nature. Hummingbirds benefit by getting nectar from the flowers. How would the flowers benefit in return?
A. The fragrance of the orchid flowers spreads farther.
B.The orchid flowers get pollinated.
C. The orchid flowers get protected.
D.The orchid flowers are able to attract more insects.
which one?
Which of the following are true about both the sun and the stars? Choose the three correct answers.
A.
Both are visible during the day in summer.
B.
Both move across the sky from east to west.
C.
Both change positions in the sky due to Earth's revolution.
D.
Both are visible at night in winter.
E.
Both appear in different positions in the sky due to Earth's rotation.
F.
Both move from north to south in the sky
Answer:
B. Both move across the sky from east to west.
C. Both change positions in the sky due to Earth's revolution.
E. Both appear in different positions in the sky due to Earth's rotation.
Explanation:
Sun and stars doesn't move in the sky. We see sun and stars move from east to west, it is due to the rotation of earth, not the movement of sun and stars.
Sun and stars are luminous objects, so only sun is visible at daytime and starts are not because sun is more luminous than stars.
Answer:
b,c and e
Explanation:
The term 'synapsis' is associated with which process?
The term 'synapsis' is associated with crossing over process.
Explanation:
An exchange or reciprocal segmental switch between chromatids of a homologous pair of chromosomes that results in a gene recombination, is understood as a crossing over. Synapsis is the fusion of two homologous chromosomes occurring while meiosis.
Synapsis enables the alignment of homologous pairs and probable chromosomal fusion between them previous to their division. The synapsis happens during meiosis prophase I. Crossing over takes place during prophase I of meiosis until tetrads are paired in metaphase I along the equator. Even sister chromatids survive by meiosis II, and homologous chromosomes were transferred to separate cells. Notice that the point of convergence is to raising genetic variability.
what is phototropism?
Answer:
Phototropism is the orientation of a plant or other organism in response to light, either toward the source of light (positive phototropism) or away from it (negative phototropism).
Explanation:
Answer: Growth towards or away from light
Explanation:
what is the habitat of a hummingbird clearwing moth
Answer:
It is found in a wide variety of habitats which includes open meadows,forest edges, and some suburban gardens.
Explanation: these are birds which fly during the day unlike most of sphinx moths that fly at night.
They feed on flower nectars
All chordates live in the ocean. True or false
Each give
_ of their
DNA to their offspring
~
Female
Male
+
=
genetic
Explanation:
each have phenotype and genotype
When the sun is high in the sky, your shadow is_________than when the sun is low.
A.
longer
B.
shorter
C.
wider
D.
skinnier
Answer:longe
Explanation:
Answer:
longer
Explanation:
I already took the quiz
Name the different pigments that can be found in plant leaves
Answer:
A leaf has several pigments. ..such as
green pigments-chlorophyll a and chlorophyll b
Yellow orange pigments- catotenoids and xanthophylls which are present in mature and yellow leaves
purple coloured pigmrnts are anthocyanin which could be seen in dome leaves specially in winters.
Explanation:
Which of these is not a form of pollution caused by humans? A.light B.chemical contaminats C.volcanic activity D.noise
Answer:
Volcanic pollution
Explanation:
How many alleles for blood type in humans?
Answer:
four blood types, a, b, ab , and o,
Answer:
3 Alleles
Explanation:
There are mainly 3 alleles for blood types IA, IB and i. IA and IB are dominant and i is a recessive allele.
Allele. Blood group
IA. A
IA, IB AB
IA, i A
IB B
IB, i B
ii O