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3 years ago

Summarize how cells regulate the cell cycle. choose from the list of words to complete the paragraph

1 answer:

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Cells use cyclins and cyclin-dependent kinases to control the cell cycle. Different combinations of cyclin/CDK start the cell cycle at different checkpoints and monitor the cycle for quality control. In G1 stage, the cell is growing and preparing to replicate DNA. DNA replication occurs in the S stage . In G2 stage , the cell takes inventory to ensure it is ready to proceed to mitosis . If the spindle apparatus malfunctions, the cycle won’t proceed to cytokinesis.

Each stage of the cell cycle has related cyclins that help the progression of that phase. Cyclins bind to cyclin-dependent kinases and activate them. The kinases are therefore able to phosphorylate particular protein and activate or deactivate them appropriately to progress the particular cell cycle stage. P53 tumor suppressor protein proteins help regulate this progress at each checkpoint. They do so by activating CDK inhibitors when required (such as when there is damage to the cells DNA).

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_____ provide defense against viruses, abnormal cells, and other intercellular pathogens.

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Cell-mediated immunity provides defense against viruses, abnormal cells, and other intercellular pathogens.

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3 years ago

What makes up a community?

serg [7]

Answer:

an interacting group of various species in a common location

Explanation:

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3 years ago

Sodium ions, oxygen (O2), and glucose pass directly through lipid bilayers at dramatically different rates. Which of the followi

Elodia [21]

Answer:

The correct order, from fastest to slowest, for the passage of molecules and ions through the cell membrane is oxygen, sodium ions, glucose (option D).

Explanation:

The plasma membrane is a lipid bilayer, with glycoproteins and membrane proteins, which constitutes a semi-permeable barrier to the passage of substances into and out of the cell.

The speed with which a substance can pass through the membrane depends on its chemical properties -hydrophilic substances pass through with greater difficulty than lipophilic ones- requiring in some cases specialized transport mechanisms. The different rates with which a substance passes depends on this.

Oxygen (O₂) passes through simple diffusion, depending on a concentration gradient. It's the molecule that passes through the membrane the fastest.
In second place, there would be the Na⁺ ions -charged atoms- that cross the membrane by facilitated diffusion, through specific ionic channels.
The glucose molecule, being larger, requires the use of transport proteins, being its passage through the membrane slower with respect to oxygen or sodium.

Undoubtedly, molecular weight and affinity for the plasma membrane are determining factors for the passage of molecules through the lipid bilayer.

Learn more:

Simple diffusion and active transport brainly.com/question/6420224

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3 years ago

Differences between Interdisciplinary and Multidisciplinary subject

Anit [1.1K]

Multidisciplinarity draws on knowledge from different disciplines but stays within their boundaries. Interdisciplinarity analyzes, synthesizes and harmonizes links between disciplines into a coordinated and coherent whole.

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3 years ago

1. Increased efforts to conserve areas such as rain forests are necessary in order to

Nataliya [291]

Answer:

1. Protect biodiversity

2. An indicator species

3. Biomagnification

4. Cutting down all the trees for lumber

5. Bioaccumulation

Explanation:

1. Conserving areas such as rain forests protect biodiversity because rain forests hold one of the highest biodiversity. They carry different types of resources that support different forms of life and at the same time, the organisms that live there support each other as well.

2. An indicator species is an organism that scientists can observe to see if there are changes in the environment it lives in. They judge the change or the implications based on the absence of the species in the environment (in which they used to be present), the presence of the species, and markers of adaptation due to the change in the ecosystem.

3. Biomagnification is a term used when contaminants that were consumed by the organisms in the lower trophic level are passed on to the next trophic level in higher concentrations. This is why those in the highest trophic levels are affected the most because they get the higher concentration of contaminants. DDT was banned when this phenomena was observed.

4. The greatest decrease in rain forest stability would be due to the cutting of trees. We can disrupt stability by gathering resources like nuts from some trees or when you remove one species of plant for medicine. However, the trees are an essential part of the rain forest because each part or area of the tree support different organisms. By cutting the whole trees off and several of them, you doom the organisms that rely on them as well.

5. As mentioned above, bioaccumulation is often interchanged with biomagnification but they differ in the usage of the terms. Like biomagnification, it talks about the accumulation of contaminants in organisms that ingest or absorb them. But bioaccumulation is a term used in a smaller scale, where it talks about the accumulation of the contimants in the tissues of the organism and not how they are passed on.

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3 years ago