Essays on Actin

Muscle contraction is a very important activity that enables an organism perform various bodily movements and flexible actions, in response to nerve stimuli. Muscle fibers are multinucleated long cylindrical cells that have an outer membrane called sarcolemma, and are mainly composed of contractile elements called myofibrils (Dougherty, 2016). Myofibrils are made up of repeating units called sarcomeres. Sarcomeres in turn are composed of (thin) actin and (thick) myosin protein filaments called myofilaments (Dougherty, 2016). The muscle fiber structure and organization is shown in Fig 1.

Contraction Mechanism – Sliding Filament Theory

According to the sliding filament theory, during contraction myosin filaments remain constant in length, ...

Chapter #16:

Question 1. Insect-eating birds will decrease in number since their source of food has been reduced. The birds may also migrate to warmer areas during this period.

Question 2.

The habitat is the specific place where the organism lives e.g. a fish’s habitat is water. On the other hand, niche is the position and the role played by the organism in an ecosystem. It includes how the organism obtain food and shelter, the mode of survival, and the mode of reproduction (Sutton & Anderson, 2009, p. 46). For instance, a lion’s niche in the ecosystem is that of a predator.Question ...

- The stromal cells that are found in the developing gonads of tetrapods begin from the medulla from the peritoneal wall and the cortex from inter-renal blastema or mesonephric. Hence the gonads have a dual origin. - Spermatogenesis occurs in a syncytial complex because it involves the formation of sperm from undifferentiated cells that are first attached to rachis. Syncytial cell complex or syncytium result when cells with single nuclei fuse to for a cell with nucleus. Syncytial cell complex is vital in oogenesis in that it assists in the differentiation of cells. One other developmental model is vitellogenesis. - ...

Introduction

Cells are independent units of life. However, when a cell becomes part of an organism, it becomes part of a tissue and organ system. Cells in a tissue are joined to each other and to the extracellular matrix (ECM) by cell junctions. There are three kinds of cell junctions: Occluding junctions, anchoring junctions and communication junctions. Occluding junctions occur in the epithelium where the adjacent cells are so tightly sealed together that even small molecules cannot pass. Communicating junctions allow the exchange of chemical and electrical signals between cells. Anchoring junctions are the ones which attach a cell either to its neighbor or ...

Introduction

As a multi-functional protein, Cytoplasmic Actin can be found in all eukaryotic cells at higher concentration levels of over 100 μM. It is the most abundant protein found in most eukaryotic cells, which makes it a critical player in different cellular functions, such as maintaining cell shape and polarity to transcription regulation. The structure of Cytoplasmic Actin is distinguished by a large number of polymorphic proteins which form the filaments. In eukaryotic organisms, such as archaea and eubacteria, actin-like proteins activities are related to sub-cellular organization, motility, cell shape maintenance and cell cycle progression; they are either associated to cell membrane or ...

Structure and Functions of Cytoplasmic Actin

Cytoplasmic actins refers to the conserved proteins. Actin can be found in all eukaryotic cells, and are involved in variety of cell motility. Protein structure is formed by combination of variety of amino acids by losing the molecule of water. Proteins get involved into variety of biological functions, and proteins have different types of structures depending upon the requirements. This paper intends to discuss different types of protein structures, their functions and other related aspects. The structure of proteins can be divided into three categories i.e. primary, secondary and tertiary. The structures of proteins are polypeptides-sequences that get ...

The regeneration of nerves throughout the human body has been a subject of much interest in biology recently. The unique characteristics of both the central nervous system (CNS) and the peripheral nervous system (PNS) provide insights into the mechanisms occurring after once damage occurs. A good understanding of tThe differences between these mechanisms also may lead to new therapies for nerve-damaged patients, including stroke patients. Following injury, the nerves in the CNS of an adult mammal will not regenerate, while the PNS will. These differences appear in every stage of axon regeneration. Within hours of axotomy, the PNS begins ...

Embryonic stem cell is a crucial factor in the developmental process of a multicellular organism. Embryonic stem cells (ESCs) are derived at early stages during development and eventually give rise to all type of tissues and organs in an animal. The ES cell lines have three properties consisting of self-renewal, primary chimera formation and pluripotency [1]. Pluripotency, a key feature of ESCs, refers to the capacity of a cell to differentiate into several different types of tissues [2]. An array of cellular factors play important role in maintaining pluripotency and determining cell fate in the developmental pathway. Negative effects on these factors may ...

Discussion of the Dynamics of Endoplasmic Reticulum And Mitochondria

Introduction The Endoplasmic Reticulum (ER) of an organism forms an interconnected membrane network that extends from the outermost nuclear to the periphery cell wall. Mitochondria are a group of cell organelles that undergo fusion and fission at a constant rate. . In plants, daily regulation of energy is important for optimal growth thus mitochondria are important for integral regulation of the cellular responses for the survival of the plant. . In this paper, we are going to discuss the dynamics of ER and the mitochondria in plants by looking at the importance of Lat.B, AA and MV regulation energy in treated and ...

Question 1

The cerebellum is an essential part of the neuromuscular system in that it plays major roles in the timing of muscular activities and the smooth progression of one muscular movement to the next. The summary of how this is done is that it sequences all the muscular activities necessary for a particular movement, and then makes corrective adjustments as necessary when the movement is being executed so that they conform to the motor impulses being generated by the cerebral cortex and other significant parts of the central nervous system (Ganong, 2005). For instance, for an individual holding a cup and ...

Mitosis is an essential process in the cell cycle for the growth and development of an organism. Over the years, numerous studies have been conducted to understand the dynamics of mitosis and literatures about the process are fast accumulating. However the mechanism that is important in the vicissitudes of cellular shape during mitosis has remained unknown. Until later, a groundbreaking research on a “small ubiquitin-related modifier” (SUMO) will unravel the mystery that takes place when the cell changes its shape during mitosis. It is a general knowledge that during the early stage of mitosis, the cell takes a round shape at the ...

1.0 Mitochondria in eukaryotic cells Organelles are special compartments surrounded by a bilipid membrane which separates them from the rest of the cell which carry out specific functions. An example of an organelle is the mitochondria which are known to be the “powerhouse of the cell.” They have their own genome (mtDNA) and are semiautonomous. They are said to have evolved from a free α proteobacterium like organism (Takasugi, Yagi, et al., 2010). The word mitochondria is derived from two Greek words: “mitos” which means thread and “chondros” which means “grain”. These two words offer an apt description of the morphology ...

According to an article written on November 14th, 2011, in New York Times by Donald McNeil on recent research findings on sickle cell anemia element responsible for its protective nature when it comes to malaria, a lot could be deciphered. Donald first provides an overview of the prevalence of Sickle cell anemia in West Africa and how it can be inherited either resulting to sickle cell trait or sickle cell anemia (McNeil, 2011). The article begins by providing a summary of the morphological changes that occurs at the red blood cell level when a malaria parasite enters a given cell (McNeil, 2011). Donald ...

The experiment essentially investigates the association between endoplasmic reticulum and mitochondria.

Introduction

Mitochondrion is a cell organelle, which moves along actin filaments. They are also calcium storage sites in the cell. The positioning and movement is influenced by membrane-cytoskeleton interactions. Reports suggest that the release of calcium from mitochondria and endoplasmic reticulum is influenced by structural changes in microtubules.

Materials used.

1. YFP-HDEL/atp-mito-CFP line. 2. 2μM Latrunculin-B 3. Ethanol control. 4. Arabidopsis Sail359/Aequroin line expressing atp-GFP-Aequorin.

Procedure

Actin depolymerization affects mitochondrial clustering and movements. In the experiment, YFP-HDEL/ atp-mito-CFP line was treated with 2μM lat-B for 3 hours and ...

Muscular dystrophy is an inherited disease where the different genes that control muscular function are defective (Emery, 2008). It has been found that many forms of dystrophy are caused by a deficiency in dystrophin, which is a muscle protein (Emery, 2008). This disease is not infectious and cannot be acquired from any activity. It is characterized by muscle weakness and wasting where the specific muscles affected vary for different types of dystrophy (Emery, 2008).

Among the various types of muscular dystrophy, the Duchenne muscular dystrophy is the most prevalent, with an occurrence of twenty to thirty cases for every one ...

Latrunculin B, methyl viologen and Antimycin A treatments on plant mitochondria which is the powerhouse of the cell. They all cause respiratory and metabolic inhibition directly or indirectly. Hence some are employed as herbicides and some used mainly experimentally to inhibit the respiration process in plants

The cell is the smallest unit of all living things. Both plants and animals are made up of cells which is the centre of control of all activities. These cells in turn are made up of several organelles like the nucleus, the cytoplasm, the nucleolus and the mitochondria all working as a team. Both ...

is this in the references?

Assignment 1: Molecular Cell Biology

3001BPS Molecular Cell Biology 2012 Assignment 1 Instructions: Use onlythe 9pages and spaces as provided. Type all textusing at least 10 point font. Diagrams should be hand drawn. PART A

Genetic studies for identifying genes involved in lysosome biogenesis led to the identification of a gene encoding a novel protein of approximately 80 kDa. An antibody was raised in rabbits to investigate the subcellular localisation of the protein using both immunofluorescence microscopy and immunogold electron microscopy. Mouse monoclonal antibodies to a known lysosomallumenal protein, hydrolase , were used as controls in these experiments. The results ...

Muscle plays important roles in the body. Those roles are attributed to the uniqueness in its anatomy and physiology. There are different types of muscles. This extends to its structures and functions. There are smaller which are in the groups of the ocular muscles and the bigger muscle in the range of biceps. It is an organ system which is usually categorized into three major forms. These are the skeletal muscles, smooth muscles and the cardiac muscles. The location, structures and function of each category is different. The major functions that is being performed by this organ is related ...

Actin in Plant Cells

Actin, one of the most abundant proteins, occurs in all eukaryotic cells constituting almost five percent of cellular protein. Actin is the predominant component of the cytoskeleton. It is worth noting that the all-important cytoskeleton of a plant has three principal components; actin filament, microtubules and intermediate filaments (Jeon, 2003). As a component of the cytoskeleton of plant and animal cells, actin is of crucial importance in a plethora of cell processes that act in concert to govern cell growth and morphology. The cell processes influenced by the actin cytoskeleton include; cell division, organelle movement, vesicle trafficking, organelle motility, and cell signaling, ...

Mitochondria and Endoplasmic Reticulum

Literature Review

Literature Review - Interactions Between Mitochondria and Endoplasmic Reticulum and Mitochondria Calcium Dynamics The interactions between mitochondria and endoplasmic reticulum in plants have great significance in the ability of the plant to self regulate, grow well and even fight off toxins. Calcium is very important for strengthening cell walls (Holdaway & Helper, 2003). The dynamic of calcium up-take has been studied since the 1800s due to the importance calcium has as a regulator for successful growth and development of plants (Hepler, 2005). The intricacies of the part Calcium plays in intracellular reactions which regulate growth and development ...