The study of cells, their physiological properties, structure, environmental interaction, division, life cycle, and death, as well as the organelles they contain. Also known as cytology.

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Why are red blood cells considered to be cells?

Wikipedia states that a cell is the basic structural, functional and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently. It then ...
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214 views

How does Cro protein expressed by lambda phage kill its host?

I read that the DNA segment of lambda phage integrated in host DNA could switch between lysogenic state where cI represses the expression of Cro and lytic state where Cro expression takes over and ...
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43 views

Can mexican salamander regenerate any organ?

Mexican salamander or few other species of salamander can regenerate limbs, tail etc. Do they have HOX genes for vital organs like liver, heart, brain, kidney? If brain is damaged, can salamander ...
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127 views

Why is chromatin not condensed during interphase but is in prophase [closed]

Cell cycle goes through three processes: Interphase Mitosis Cytokinesis Why are chromatins not condensed during interphase but instead condensed at prophase of mitosis? What makes them condense ...
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4answers
202 views

Recommend good conversational books to learn about cell and developmental biology or biochemisty?

I'm an engineer by training and teaching myself the basics of cell and developmental biology. I'm using Scott F. Gilbert's Developmental Biology and Alberts' Essential Cell Biology right now, and they ...
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10k views

Why was the Davson-Danielli model rejected?

According to my textbook, Davson-Danielli's model of a phospholipid bilayer sandwiched between two layers of globular protein was incorrect. The nonpolar protein portions would separate the polar ...
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29 views

What's the purpose of Cdk activity having more than one method of becoming inactive?

Cdk becomes partially active once its bound to cyclin and then gets phosphorylated and fully active once a Cdk-activating kinase (CAK) phosphorylates the partially active Cdk. This fully activated Cdk ...
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5answers
7k views

Why do cell membranes have a lipid bilayer?

Many cells have a cell membrane composed of two layers of lipids, why is it two layers and not just one? What purpose do the membranes serve?
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3k views

Complementarity Determining Regions (CDRs)

Complementarity determining regions (CDRs) are part of the variable domains in immunoglobulins (antibodies) and T cell receptors, generated by B-cells and T-cells respectively, where these molecules ...
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268 views

How can a polar molecule pass through polar channels of proteins in the cell membrane?

To transport a polar molecule through the nonpolar cell membrane, a protein with a polar channel is needed to allow it to diffuse. However, if the molecule is polar and the channel is polar, wouldn't ...
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165 views

Why do animal cells lack a contractile vacuole?

I was asked why animal cells do not have contractile vacuoles. Other than the lack of need, I don't know what else to say.
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45 views

Determining the osmolarity and tonicity of a cell

Consider a cell with urea concentration inside being 2mmol/L and outside being 2.5mmol/L. The cell itself is permeable to both urea and water. Ignoring the effect of other osmolytes, A) Urea flows ...
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25 views

Gene silencing in C. elegans

I am trying to silence the tph-1 (tryptophan hydroxylase) gene in C. elegans using the pLT63 plasmid to check if that particular gene has anything to do with the pharyneal pumping or not. Am I using ...
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4answers
141 views

Can general soap kill bacteria?

I have read that general soap can kill bacteria by opening holes in the bacterial membrane. http://questions.sci-toys.com/node/90 However, I found some articles as well saying that it cannot. ...
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3answers
3k views

Why do cells vary in shape and function when they have the same genome and the same organelles?

Why do cells vary in shape and function when they have the same genome and the same organelles. For example: why do all cells have nuclei but red blood cell's don't; why can't the cells of a eye ...
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2answers
12k views

How do plant cell divide without centrioles?

Most plants do not have centrioles , so What organelle lets them multiply?
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59 views

Purpose of antibody wash

It is common practice after surface staining cells for flow cytometry analysis to wash the antibody out of solution before analyzing a sample. I have tried analysis with and without washing the ...
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137 views

Is there a database of cell images?

We're working on an algorithm for processing images of cells, similar to but much more basic than Cell Profiler, and we are looking for a large database of cell images to test our software. Can anyone ...
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156 views

What is the mechanism by which lamins regulate gene expression?

The heterochromatin is generally localized at the nuclear periphery (also near nuclear lamina), whereas active genes are preferentially found in the nuclear interior. Children with ...
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1answer
63 views

Is there any possible way to take a DNA test without using blood in humans?

Is there any possible way to take a DNA test without the need to draw blood in humans? Any information will be useful for me.
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3answers
85 views

Why are embryonic germ cells considered stem cells?

In a class that I'm taking we were presented 3 types of stem cells. Adult stem cells which come from bone marrow Embryonic stem cells which come from embryos Embryonic germ cells which come from ...
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What is the difference between “dikaryotic” and “heterokaryotic” states in the sexual lifecyles of fungi?

Many fungi undergo a reproductive phase in which more than one genetically distinct nuclei (from 2 separate mating types) is present within the same cytoplasm. In the Ascomycota and Basidiomycota, ...
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38 views

How can rapid growth cancer get nutrients in vivo?

When I was little, before I get into biological studying, I read a news talking about cancer would be totally cured after decades. I still remember that researchers had a theory to claim if they could ...
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1answer
2k views

How can Valonia ventricosa cells get so big?

Valonia ventricosa are single celled algae that range between one and few centimeters. In rare cases they can reach sizes exceeding 5cm. They range from grass green, to dark green, and some are even a ...
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44 views

yeast colonies pulsing out soft fringes against the light

I have no idea about this part of the following text "pulsing out soft fringes against the light". Can anybody explain about it and provide some images, please? Does it mean that these colonies ...
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1answer
63 views

How can E. coli affect C. elegans expression?

Plasmids can be transferred to E. coli. These transformed E. coli can be fed to C. elegans to silence its gene expression by RNAi. How can E.coli release RNAi to C. elegans? Even if we assume E. ...
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245 views

Are mitochondria alive? [duplicate]

I'm working on an assignment for my IB biology class and some assistance would be highly appreciated. I've read several articles and I still haven't quite gotten the answer I'm looking for. I have to ...
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32 views

how often do the various organ cells regenerate? [closed]

Is there an Internet source that states how often human organ cells (eyes, kidneys, liver, heart, pancreas, skin, etc.) regenerate? I'm seeking specific data for every human organ.
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68 views

which organelle produce glycogen phosphorylase and why

I know that Glycogen phosphorylase doesn't produce from rough endoplasmic reticulum in liver cell. But almost every proteins such as insulin receptor, serum albumin, and lysosomal enzyme have to ...
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16 views

Growth of Yeast in Different pH Mediums

Will yeast grow better in acidic, basic or neutral mediums? Why? Will the medium affect the growth of yeast? (Yeast cell membrane is semi-permeable).
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323 views

Why do some white blood cells have lobed nuclei?

Several types of white blood cells (eg Neutrophils) have lobed nuclei. Is this for a functional reason? I have seen people refer to structural differences in the lobes as indicative of problems, but ...
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8k views

Rate of cell division in humans

On average, how many cells divide each day in a human being? How long does a cell wait before dividing itself ? I have tried to look on the internet but surprisingly the answer is difficult to ...
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3answers
787 views

Do we consume dna, proteins of other organisms?

When we eat raw meat, e.g. chicken or fish, we are actually consuming the DNA, proteins etc. which are present in their cells. Wouldn't this affect our cell functions as this DNA might enter our ...
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1answer
159 views

Membrane Permeability to Pyruvate

Pyruvate seems to pass easily through the outer membrane of the mitochondrion but has difficulty entering the inner membrane (and gets in by H+ symport). I have two questions: (1) what property of ...
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52 views

What are the sizes of the cells that make up human hair?

The question is in the title, but I'll explain why the question arose. I'm curious about the rates that various cells in the body divide, and have found various information relating to this, but ...
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36 views

How to use DRAQ5 and MitoTracker CMXros dyes to stain turtle erythrocytes?

I am working on turtle species and want to use DRAQ5 and MitoTracker CMXRos to stain turtle nucleated erythrocytes. Can anyone suggest me a protocol to carry this stain out? Would the two stains ...
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1answer
67 views

Introductory book to cell biology

I am studying the human circulatory and respiratory systems to develop tools for automated diagnosis of disease. During the past year, I have read basic books about respiratory physiology, ...
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1answer
72 views

Why do cells not spread on soft substrates?

I recently read a paper discussing how cells (primary mouse embryo fibroblasts) fail to spread and proliferate properly when plated on a soft substrate (i.e. soft PDMS pillars with stiffness k = 2.3 ...
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Do animal cells have vacuoles?

I overheard a rather heated argument about whether or not animal cells have vacuoles. One person said that they do, but they're much smaller than vacuoles in plant cells. The other person said they ...
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74 views

What is the essence of difference of how different chemicals affect the same receptor?

It is known that various chemicals can bind to the same receptor type, producing different effects. Be these chemicals agonists or antagonists, there are more variations in how they influence the ...
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1answer
699 views

How is centriole number maintained during meiosis?

I've found a website (Pearson's BioCoach) that claims centrioles duplicate in Prophase II. Is this accurate? Does it depend on the species in question? Looking at three textbook illustrations of ...
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1answer
253 views

How to understand certain protein names

I am looking for a reference to help me understand what is meant by acronyms such as : H3K9me1, H3K9me2, and H3K9Ac. I know that these are all histone proteins, but is there a general nomenclature ...
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44 views

Self assembly of Golgi Apparatus

Self assembly is not a new phenomenon to biology. Many things self assembled to provide full fledged functional unit. There are two conflicting theories about formation of Golgi Apparatus, Template ...
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3answers
366 views

How crowded is the bacterial cell?

I was wondering what is the protein concentration in an E. coli cell. When studying enzyme kinetics and activity in vitro, I would argue that the substrate and enzyme concentrations resemble those in ...
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1answer
116 views

Catenation and decatenation by DNA Gyrase

Decatenation is done for the replication of DNA and why is Catenation done and is it related to Crossing over
2
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1answer
128 views

What is a mechanical cue?

I was attending a talk related to neurogenesis. So one professor was asking a question related to biochemical cues and mechanical cues (related to signaling pathways I believe). Cue as far as I ...
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1answer
136 views

How will changing the concentration of a Tris buffer affect amylase enzyme activity?

For instance if you increase the amount of Tris but pH still does not change then will the enzyme activity still proceed normally? If it does change the pH will it change enzyme structure and why?
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2answers
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Question about flux and changes in net flux of molecules across a membrane

I've been reading a book called Principles of Human Physiology by Stanfield 5th edition, and was reading a chapter on membrane transport when I came across a figure question which will be posted ...
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1answer
86 views

How do single-celled predators chase other cells?

From my understanding, single celled organisms have been seen avoiding, and chasing, potential food or other organisms. How do they accomplish this? They do not have eyes or ears or a nervous system. ...
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1answer
60 views

Why are siblings unidentical? (Which chromosome of the pair do gametes have?) [closed]

I know that a normal human cell has 23 pairs of chromosomes (total: 46). On the other hand, a gamete has only 23 chromosomes. Which chromosome does the gamete choose out of each pair? And if "One of ...