Answer:
Natural selection is a mechanism of evolution proposed by Charles Darwin. It is the differential survival and reproduction of individual due to the difference in the phenotype. Over time, this process results in populations which are better adapted to their environment as they tend to survive and produce new offspring. The brown squirrels with thick coat survive at a higher rate than the brown sqirrels without the thick coat. Thick coat is a adaptation for survival in cold winters which are chosen over the other and allowed to reproduce.
Explanation:
From a single fertilized ovum undergoing a series of rapid cell divisions, a human infant develops. The embryonic cells become specialized for a variety of functions. Which of these statements best describes how different cell types develop?
A. Each cell type contains only the active parts of the DNA needed for that cell type.
B. Each cell has multiple copies of DNA that are affected in different ways by the environment to change the function of the cell at regular intervals.
C. Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells.
D. Each cell type has only one chromosome containing thr DNA needed for that cell type.
Please help ill give you 5 star and brainliest.
Answer:
Answer is C
Explanation:
Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes leading to a variety of cells
The statements 'each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells' BEST describes how different cell types develop (Option C).
Epigenetics refers to any change in gene expression that does not involve a change in the nucleotide sequence.In an organism, all somatic cells are genetically identical, thereby changes in gene expression are due to epigenetic modifications.These epigenetic modifications include DNA methylation and histone modifications (e.g., histone acetylation, histone methylation, etc).Enzymes that add specific epigenetic marks such as histone acetyltransferases alter the accessibility of transcription factors to chromatin, thereby activating or repressing gene expression.In conclusion, the statements 'each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells' BEST describes how different cell types develop (Option C).
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a metacentric chromosome is one that has a centrally located centomere and chromosome arms with approximately equal length. which of the human chromosomesare metacentric
Answer:
Human chromosomes 1 and 3
Explanation:
There are four types of chromosomes classified based on the position of their centromere. These chromosomes are metacentric, submetacentric, acrocentric and telocentric. As rightly stated in this question, metacentric chromosome is the chromosome that has a centrally located centomere making the chromosome arms to be approximately of equal length.
The metacentric type of chromosomes are present in humans as viewed using KARYOTYPE (a pictorial display of chromosome arrangement). Based on karyotyping, chromosomes 1 and 3 are METACENTRIC.
Wild diploid wheat has seven chromosomes in its pollen. Discuss the major events that had to occur for tetraploid pasta wheat to have evolved. Describe the genome and fertility of pasta wheat (number and kinds of chromosomes).
Answer:
Tetraploid wheat evolved by allopolyploidization and subsequent diploid-like behavior due to cytological diploidization
Explanation:
Durum wheat (Triticum durum) or pasta wheat, is a tetraploid wheat species that has 28 chromosomes, i.e., seven pairs in each genome (2n = 4x = 28). Durum wheat was domesticated from wild emmer wheat, which originated by hybridization of two diploid wheat species with 14 chromosomes: Triticum monococcum (genome AA) and one wild progenitor (genome BB). Triticum durum is a typical example of evolution by hybridization and polyploidization, where the resultant tetraploid species has two complete sets of chromosomes. Allopolyploidization is one of the most common types of plant speciation. During meiosis, 28 chromosomes form 14 homologous chromosome pairs, because homologous chromosomes have developed 'restriction of pairing' (i.e., cytological diploidization). The restriction of pairing to fully homologous chromosomes ensures a correct meiotic behavior, which otherwise would be altered due to the high level of homology that still exists among chromosomes from different wheat progenitors.
The energy given off by burning fossil fuels can be measured in
A) Joules
B) calories
C) Hertz
D) electronvolts
Answer:
A
Explanation:
A
Answer:
A
Explanation:
Joules are used to measure energy
In which form food is stored in the leaves? Comment
the answer is starch
Explanation:
food is stored in the leaf in form of starch in plants
NEED HELP RLLY BAD
where are excessive ketones normally seen in a test?
1. blood
2. urine
3. saliva
how to get sick with fever fast
Answer: Over exhaust your self and stay up for two days no sleep.
how do unicellular and multicellular organisms differ?
Answer:
Unicellular organisms- Organisms which have only single cell are called unicellular organisms.
Multicellualr organisms- Organisms with many cells are called multicellular organisms.
Answer:
multicellular organisms need organs to function properly
Explanation:
What happens to the actin and myosin during a muscle contraction?
Answer:
Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.
Cell _________
is the process by
which cells divide
Answer:
Cell cycle
Explanation:
Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell devides to produce two identical daughter cells.
Need help ASAP 48 points
4 questions and map on top ASAP :)
A teacher asked her students to transcribe a DNA sequence into a complementary RNA strand. She gave the students the following DNA code: AGC TTA GGC. Which student created the correct RNA strand?
Student 1
CUG AAC UUG
Student 2
AGC UUA GGC
Student 3
TCG AAT CCG
Student 4
UCG AAU CCG
Question 4 options:
a.student 3
b.student 2
c.student 1
d.student 4
Answer:
student 4 bcoz thymine is replaced by uracil in RNA
Answer:Student 4
Explanation:
The region in a plant that is analogous to animal stem cells, and can develop into various types of tissues and organs, is the ______.
he root system includes those parts of the plant below ground, such as the roots, tubers, and rhizomes. Plant cells are formed at meristems, and then develop into cell types which are grouped into tissues
"Can dogs identify colors?" is an example of a scientific question. "Are dogs better pets than cats?" is not. Use complete sentences to explain the difference between these questions and why only one is scientific. (5 points) Your answer:
Which helps in the production of eggs?
testosterone
estrogen
semen
fallopian tube
Answer:
Semen helps in the production of eggs!
answer:
... semen...
explanation:
i'd be embarrassed to explain that bit
Need help! 40 points!
Answer:
Row 3 should be it.
Explanation:
From how many stem cells does cell division take place in meiosis?
Answer:
They probably divide to make EITHER two stem cells, OR two more specialized cells.
Explanation:
Doctors are investigating the case of a patient with defective proteins.
Which organelle is most likely the cause?
A. lysosome
B. cell membrane
C. cytoplasm
D. ribosome
Answer:
Answer is D
Explanation:
I also took the test as well and got 100% on it
Natural _______is a mechanism for the evolution of a population to become better adapted for survival in a specific environment.
Answer:
natural selection
Explanation:
define asexual reproduction help plz
What is the most common weather patterns for the tropics?
Your answer
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In humans, earlobes that are suspended (detached) are dominant over those that are attached. If a mother has suspended earlobes (but her mother did not) and the father has attached earlobes, what are the chances that their first child will have attached earlobes?
Answer:
i would say it is a 50/50chance
Explanation:
Describe the resting state of a neuron.
The long whip-like structure that helps a cell move and gather food is called a
A. flagella
B. cilia
C. false foot
D. whipper
Answer:
flagella
Explanation:
It helps the cell move
these minerals are formed through crystallization of molten materials which statement best describes these two minerals?
the mineral on the left formed from lava
the mineral on the right formed from magma
the mineral on the left has smaller crystals in the middle on the right
the mineral on the left cool more slowly than the mineral on the right
Answer:
The answer is D.
Explanation:
Just took the quiz and got it correct.
The correct statement is that the mineral on the left cool more slowly than the mineral on the right
The crystallization process is simply known as the way through which atoms are arranged to form a material with a crystal structure.
A ways minerals is formed is by:
Crystallization of magma or lava
The minerals that forms igneous rocks often solidify or freeze at different temperatures.
Magma are created underground, in the lower crust or upper mantle, due to the intense heat there.
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Human protein X is encoded by human gene X. Gene X consists of 4 exons of 200 bp each, interspersed with introns of 1,000 bp each.
An mRNA cap will be found on ____________.
a. the primary transcript
b. the mRNA
c. at least one of the lariats
d. the poly(A) tail.
e. exon 1
f. all exons
g. some introns
Answer:
a. the primary transcript
Explanation:
The first step in RNAm maturation is the modification of the 5' end of the transcript via the addition of a structure called a cap or 7-methyl guanosine cap. The enzymes responsible for the formation of this cap are recruited to the phosphorylated C-terminal domain after the addition of the first twenty to thirty nucleotides of ARN. The formation of the cap is started by the addition of a GTP molecule oriented inversely to the 5' end nucleotide on RNA. Then methyl groups are added to this G residue and to the ribose forms of one or two nucleotides located on the 5' end. All these reactions take place in the nucleus when the mRNA is found as a primary transcript.
What were the ancestors of mitochondria according to the endosymbiotic theory?
20 points
A. Aerobic eukaryotes
B. Aerobic bacteria
C. Anaerobic bacteria
D. Chloroplasts
Answer:
d is your answer
Explanation:
Ancestors of Mitochondria were aerobic bacteria, according to endosymbiotic theory.
What is endosymbiotic theory ?According to Lynn Margulis' endosymbiotic theory, mitochondria in eukaryotes are thought to have originated via an endosymbiotic connection with purple photosynthetic bacteria around 1.5 109 years ago. The endosymbiont, which had been captured, was subsequently transformed into a useful organelle bound by two membranes. Supporting data for the endosymbiont theory.
Prokaryotic cells and mitochondria are the same size. The DNA found in mitochondria is structurally identical to bacterial DNA. Similar to bacteria, mitochondria are self-replicating cells divide by binary fission Two membranes enclose mitochondria, and the inner membrane is structurally very similar to that of bacteria.
Therefore, aerobic bacteria are the ancestors of mitochondria.
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3. When a single-celled organism splits into 2 new organisms it is called _________________. *
a.fission
b.budding
c.fragmentation
d.sporulatioin
Answer:
When a single-celled organism splits into 2 new organisms it is called fission.
When a single-celled organism splits into 2 new organisms it is called fission. Therefore, option (A) is correct.
What is binary fission?In biology, fission is the split of a single organism into two or more pieces, followed by the regeneration of those parts into new, distinct organisms that resemble the original. Cells are often the thing that undergoes fission, although the phrase may also describe how creatures, bodies, populations, or species divide into distinct sections.
Asexual reproduction in bacteria occurs via a mechanism called binary fission. A single organism splits into two separate ones during binary fission. The duplication of organelles in eukaryotes is sometimes referred to as binary fission.
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T/F In passive transport, substances move from areas of low concentration to
areas of high
A.True
B.False
Answer:
false
Explanation:
they move from high to low concentration
The cell cycle is highly regulated and involves many steps to ensure that a cell is ready to divide. For this reason, cells cycle between interphase and mitosis. Suppose a cell culture of 1,000 cells is grown, in which the cells cycle every 24 hours. For a single cell, it takes about two hours from the formation of the dissolution of the nuclear envelope to the separation of two daughter cells.
Which of the following best describes the approximate number of cells in the culture that are in interphase, as well as the consequence of the severe disruption of interphase in mitotic division of cells within a tissue?
A) There are approximately 917 cells in interphase. Disruption of interphase will have no effect on mitosis because they are two completely independent processes.
B) There are approximately 83 cells in interphase. Disruption of interphase will lead to a faster and more efficient mitotic cycle, which will result in increased cell division and tissue growth.
C) There are approximately 917 cells in interphase. Disruption of interphase will trigger the cell to switch to a mitotic phase and repeatedly divide, which will result in the massive proliferation of the cells and heightened tissue growth.
D) There are approximately 83 cells in interphase. Disruption of interphase will result in the cell being unable to synthesize proteins and organelles required to divide, which will result in the cell not passing key checkpoints and ceasing to divide.
Answer:
The two major phases of the cell cycle include mitosis (cell division), and interphase, when the cell grows and performs all of its normal functions. Interphase is further subdivided into G1, S, and G2 phases. After the synthesis phase, the cell proceeds through the G2 phase.
Explanation:
Answer:
I believe it is the first one not 100 percent tho
Explanation: