Ask Question, Ask an Expert


Ask Biology Expert

1. The three components of the eukaryotic cytoskeleton are microtubules, microfilaments and intermediate filaments.
a) State the principle protein component of the microtubules, and briefly describe the structure of a microtubule.
b) Describe how microfilaments polymerize from their monomer components. Include a description of the protein component(,0) treadmilling, and the role of ATP and capping proteins.
c) The following proteins all interact with microfilaments: ezrin, ARP complex, cofilin, myosin, fimrin. Describe the functions of three of these proteins within the cell.
d) Give one ex of a protein that may form intermediate filaments and describe the type of structures that intermediate filaments produce.

2. a) Briefly describe the main differences between integral and peripheral membrane proteins in terms of their location and interactions with the lipid bilayer.
b) Describe the arrangement of secondary structural elements in one type of multipass transmembrane protein.
c) How can antibodies raised against segments of amino acid in a membrane protein be used to provide information on the structure of that protein?

3. a) Briefly describe how the core eukaryotic nucleosome is formed from its protein components and the location of the DNA strand, in relation to the nucleosome.
b) How is the local structure of chromatin maintained during genomic DNA replication?
c) Describe what occurs to nuclear DNA in a cell that has undergone apoptosis, and describe the characteristic pattern shown by DNA from an apoptotic cell, when it is examined by agarase gel electrophoresis.

4. a) List three ways in which mature mRNA differs from the primary transcript.
b) Which of the features of mature eukaryotic mRNA, identified in )a), influence the stability of mRNA and how?
c) Briefly describe what is meant by RNA editing, how this process can occur and how it affects the protein that the RNA encodes.

5. a) Briefly describe what is meant by the term 'growth cone.'
b) What effects do the molecules netrin and semaphorin have on the process of neurit outgrowth?
c) What type of molecules are cadherins, and what effect do they have on neurite outgrowth?
d) Describe how netrin, semaphorin and slit control the growth of the axons of commissural neurons across the midline and towards the brain during development.

6. a) Briefly describe the G2 checkpoint which is sensitive to DNA damage. Use diagrams as appropriate to describe how the activities of the phosphatase Cdc25 and kinase Weee1 play a role in the control of entry into M phase.
b) describe how the positive feedback loop in this checkpoint functions.
c) What are the two principal external causes of double-strand breaks in DNA?
d) Briefly outline two mechanisms by which double-strand breaks are repaired by a cell.

7. a) Give one ex of a cell-type that may be mobile within the tissues of an adult mammal, and describe how motility contributes to the normal function of that cell.
b) Define the term 'chemotaxis' and give one ex of a molecule that can induce chemotaxis.
c) describe with the aid of a labelled diagram how molecules that induce chemotaxis can act on a cell to cause its polarization. The diagram should include information on the receptor for the chemotactic molecule and the intracellular signals and events that follow activation of the receptor.

8. a) describe the difference between reactive oxygen species and free radicals, and give one ex of each.
b) What cellular process is the main source of free radicals in eukaryotes and where does it take place?
c) What biological molecules can be damaged by interaction with free radicals? Give one ex of the way that a free radical can interact with a biological molecule to change its structure.
d) describe the different between primary and secondary antioxidant defenses, giving one ex of each.

Biology, Academics

  • Category:- Biology
  • Reference No.:- M924333

Have any Question? 

Related Questions in Biology

Please refer to the following interactive map as you

Please refer to the following interactive map as you complete this activity:  Here are instructions for how to read the map: ...

Healthy people 2020 is a framework to assist communities in

Healthy People 2020 is a framework to assist communities in preventing disease and promoting health. Search the scientific literature and find a research study related to one of the focus areas identified by Healthy Peop ...

Microbiology1 for what specific purpose was gram staining

Microbiology 1. For what specific purpose was gram staining developed for? what is it used for today? 2. Why is the presence of air bubbles a sign of contamination? 3. Why is a gram stain helpful when monitoring bacteria ...

What are the transcription factors important for muscle

What are the transcription factors important for muscle development? i.e. There are different steps to get a muscle fiber, what are the transcription factors that are important for these steps?

The effect of low ph on enzyme activitydesign an experiment

The Effect of low pH on Enzyme Activity Design an experiment in which you will test the effect of an acidic fluid on enzymatic activity. (Recall: enzymes are proteins.) To complete this project, it may be useful for you ...

You have formulated a hypothesis mangoes contain more

You have formulated a hypothesis: "Mangoes contain more vitamin C than oranges." To test this hypothesis you measure vitamin C levels in 20 oranges and 20 mangoes from trees that were grown in the same orchard under the ...

Part 1suppose you are given a new temperature sensitive

Part 1. Suppose you are given a new temperature sensitive bacterial mutant that grows normally at 37 degrees C but cannot replicate its chromosomes properly at 42 C. To investigate the nature of the underlying defect, yo ...

Wellnesssynthesize in about 250 words an overview of what

Wellness Synthesize, in about 250 words, an overview of what you have learned from the course with regard to health and wellness. How do the various aspects of wellness influence one another? How do different disciplines ...

Research and briefly describe a real world example about

Research and briefly describe a real world example about how acid rain affects plants. Be sure to demonstrate how pH contributes to the outcome, and proposed solutions (if any). Descriptions should be approximately 2 - 3 ...

Given what you know about how natural selection works

Given what you know about how Natural Selection works, explain why Sickle cell disease hasn't been eradicated from the population.

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro

Describe what you learned about the impact of economic

Describe what you learned about the impact of economic, social, and demographic trends affecting the US labor environmen