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Cell Structure

ER retrieval signal...

If you were to remove the ER retrieval signal (KDEL) from protein disulfide isomerase (PDI), which is normally a soluble resident of the ER lumen, where would you expect the modified PDI to be located?

G Protein Isolated Mutations

Siganl tansducing tirmeric G proteins consist of three subunits designated as alpha, beta, gamma. Suppose you have isolated a mutant G alpha subunit that has an increased GTPase activity. What effect would this mutation have on the G protein and the effector protein? Why?

Name the Structure with Arrow Points

Download the image (attached) 1. Name the structure to which the arrow points. 2. Give an example of a specific organism which has the structure. 3. Briefly describe at least one function the structure performs (what it helps the organism do).

Free energy vs activation energy is contrasted.

I'm having a diffucult time understanding free energy vs activation energy are they the same? I know free energy is the portion of a system's energy that is available for work but what is this compared to the activiation energy?

The Building Blocks of Biology

Often, prokaryotic cells exist as simple unicellular organisms, but in some species, prokaryotic cells can grow together in colonies or filaments. In addition, some species, such as Cynaobacteria or Myxobacteria, demonstrate intercellular communication, or might even produce specialized cells and structures. However, only euk

Physical and metabolic contraints

I need guideness on the physical and metabolic constraints limit cells size? And how an enormous cell encounter and adapations would help large cells survive?

Osmosis, diffussion and cell membrane

I am trying to compare process osmosis and diffussion and how does the two process help a plant leaves remain firm? 2. How exactly does a cell membrane structure related to its function?

Pathways Respiration is the featured topic.

Of the pathways in respiration, which one produces the least energy? The Next least? The Most? How do you know this, and why is this important to the environement we live in (ie on Earth?)? Ideas are presented.

Monera and protista

Please answer the attached questions on monera and protista. --- LAB 14- B 1- To what extent would filamentous cyanobacteria be considered multicellular? 2- Which of the following words or phrases describes the heterotrophic bacteria, the cyanobacteria, both or neither? a. lack of nuclear envelope b. photosynthesize si

It would be helpful if you have done cellular labs

Please answer the following questions (attached). --- LAB 4-A 1- What do you think is the function of the appendages extending from the nerve cells? 2- What three organelles (or structures) can you view in the elodea leaf cells, but not in the mammalian nerve cells? 3- Does Spirostomum have a cell wall? How do you kn

Must know all different types of microscopes

Please answer the following short questions (as brief as possible) This is for my study guide. --- 1A LAB 1- If an ocular lens has a magnifying power of 15X and the objective lens is 10X what is the total magnification? 2- Identify the part of the microscope with the following functions: a. Lens that further magnifi


How is programmed death of cells (apoptosis) used during embryonic development and in fighting cancer?

Plasma membrane

Give the term for the plasma membrane pulling away from the cell wall.

GAP JUNCTIONS for Multicellular Organisms

As multicellular organisms decelop from embryo to adults, gap junctions are made and broken in specific patterns, involving specific tissues. This suggests that these junctions play an important role in signalling between cells during embryonic development. A) With the understanding of Gap junctions, speculate on what sorts

Signal pathway comparison

Consider the signalling pathway that proceeds through three protein kinases that are sequentially activated by phosphorylation. IN one case the kinases are held in a signalling complex by a scaffolding protein; in the other, the kinases are freely diffusing (see figure attached). Discuss the properties of these two types of orga

Second messengers

Is it true that all small intracellular mediators (second messengers) are water-soluble and pass freely through the cytosol? Why? I know this is true, but why is it true?

Isolate peroxisomes

Hi, I have a test next wednesday and a concept is not clear to me. How would I isolate peroxisomes from cells. ( I dont need a complicated technical answer, but more of a general idea). Thanks

Transport vesicles, secretory vesicles, and endocytotic vesicles

Whats the difference between transport vesicles, secretory vesicles, and endocytotic vesicles? I know that Transport vesicles move molecules between locations inside the cell. For example they move proteins from the ER to the Golgi, from there to the outer membrane, where they are secreted

Phospholipid bilayer

What are the three chief components of eukaryotic cell membranes? Where does each originate? What organelle synthesizes new membrane? What accounts for the stability of phospholipid bilayers in acqueos systems? Would the three components be the integral membrane protein, cholesterol, and lipid? Is the ER the organelle th


What types of chemical can generally pass through phospholipid portions of the cell membrane and why? What types are generally prevented from passing through and why? I would guess hydrophillic chemicals can pass through.

Coat Proteins

The image shows the inner face of a cell membrane with numerous budding structures, each one surrounded by coat proteins. What process is going on, and what is the role of the coat proteins?

the location of ribosomes

You prepare radioactivley labelled ribosomal subunits and you microinject them into cells that you are culturing in the laboratory. At different times after you inject the subunits, you take a small amount of cells and analyze them by electron microscopy. You find very soon after injection, the labelled subunits are assembled in

COPII assembly

I am currently studying the intracellular distribution of a particular protein. The protein is normally Golgi-resident. What would happen to this distribution if i treated the cell with an inhibitor of COPII assembly? I would think that if the COPII vesicles are inhibited the ER would be unable to export cargo to the gol

What ingredients are needed for bread to rise?

Bread ingredients include milk, sugar, flour and salt. Which of these is needed for maximum fermentation by the yeast? What tests could be done in the lab? Will yeast react differently with different amounts of the other ingrediants? We did the lab and cut down the amounts of sugar, salt and milk. We had different results bu