tag:blogger.com,1999:blog-51424615119791213422024-09-11T15:33:02.973-07:00Unknownnoreply@blogger.comBlogger338125tag:blogger.com,1999:blog-5142461511979121342.post-5803242980881346192016-11-05T13:00:00.000-07:002016-11-05T13:00:06.826-07:00

Genes are small sections of DNA within the genome that code for proteins. They contain the instructions for our individual characteristics – like eye and hair colour. A gene is a small section of DNA? that contains the instructions for a specific molecule, usually a protein?. The purpose of genes? is to store information. Each gene contains the information required to build specific proteins

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-85282651138770189052013-02-27T03:11:00.007-08:002016-11-05T13:00:22.041-07:00

What are plant cell vacuoles? What are their functions? What is the covering membrane of the vacuoles called? Plant cell vacuoles are cell structures delimited by membranes within which there is an aqueous solution made of various substances like carbohydrates and proteins. In young plant cells many small vacuoles can be seen; within adult cells the most part of the internal area of the cell

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-56635365202167914802013-02-27T03:11:00.005-08:002016-11-05T13:01:10.054-07:00

Chloroplasts are organelles present in the cytoplasm of plant and algae cells. Like mitochondria, chloroplasts have two boundary membranes and many internal membranous sacs . Within the organelle there are DNA, RNA and ribosomes and also the pigment chlorophyll, responsible for absorption of photic energy that is used in photosynthesis. The main function of chloroplasts is photosynthesis: the

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-9558626313752466512013-02-27T03:11:00.003-08:002016-11-05T13:02:06.617-07:00

As the name indicates, the cytoskeleton is responsible for the support of the normal shape of the cell; it also acts as a facilitator for substance transport across the cell and for the movement of cellular organelles.  For example, the sliding between actin-containing filaments and the protein myosin creates pseudopods. In cells of the phagocytic defense system, like macrophages,

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-63812169007029355622013-02-27T03:11:00.001-08:002016-11-05T13:02:32.447-07:00

The cytoskeleton is a network of very small tubules and filaments distributed throughout the cytoplasm of eukaryotic cells. It is made of microtubules, microfilaments and intermediate filaments. Microtubules are formed by molecules of a protein called tubulin. Microfilaments are made of actin, the same protein that participates in the contraction of muscle cells. Intermediate filaments are

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-31794715316259537762013-02-27T03:09:00.001-08:002016-11-05T12:53:42.806-07:00

It is presumed that mitochondria were primitive aerobic prokaryotes that were engulfed in mutualism by primitive anaerobic eukaryotes, receiving protection from these beings and offering energy to them. This hypothesis is called the endosymbiotic hypothesis on the origin of mitochondria.The hypothesis is strengthened by some molecular evidence such as the fact that mitochondria have their own

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-39648722474552603202013-02-27T03:08:00.003-08:002016-11-05T12:53:55.129-07:00

Mitochondria are the “power plants” of aerobic cells because within them the final stages of the cellular respiration process occurs. Cellular respiration is the process of using organic molecule (mainly glucose) and oxygen to produce carbon dioxide and energy. The energy is stored in the form of ATP (adenosine triphosphate) molecules and later used in other cellular metabolic reactions. In

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-59891123239607120572013-02-27T03:08:00.001-08:002016-11-05T12:54:21.624-07:00

Mitochondria are the organelles in which the most important part of the cellular respiration occurs: the ATP production.Mitochondria are organelles delimited by two lipid membranes. The inner membrane invaginates to the interior of the organelle forming cristae that delimitate the internal space known as mitochondrial matrix and where mitochondrial DNA (mtDNA), mitochondrial RNA (mt RNA),

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-86433098330765319392013-02-27T03:07:00.001-08:002013-02-27T03:07:46.127-08:00

Lysosomes carry out autophagic and heterophagic digestion: autophagic digestion by digesting residual substances from the cellular metabolism; heterophagic digestion by digesting substances that enter the cell. Lysosomes enfold the substances to be degraded forming digestive vacuoles, or residual vacuoles, that later migrate toward the plasma membrane fusing with it and liberating (

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-21602041560036446022013-02-27T03:06:00.001-08:002013-02-27T03:06:56.892-08:00

The endoplasmic reticulum is a delicate membranous structure contiguous to the nuclear membrane and present in the cytoplasm. It forms an extensive net of channels throughout the cell and is classified into rough or smooth types. The rough endoplasmic reticulum has a great number of ribosomes attached to the external side of its membrane. The smooth endoplasmic reticulum does not have

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-35639466040373101072013-02-27T03:05:00.003-08:002013-02-27T03:05:27.787-08:00

The aqueous fluid that fills the nuclear region is called karyolymph, or nucleoplasm. In the fluid there are proteins, enzymes and other important substances for the nuclear metabolism.

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-83143283278989072012013-02-27T03:05:00.001-08:002013-02-27T03:05:23.860-08:00

The aqueous fluid that fills the nuclear region is called karyolymph, or nucleoplasm. In the fluid there are proteins, enzymes and other important substances for the nuclear metabolism.

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-69457587790202701262013-02-27T03:04:00.006-08:002013-02-27T03:04:42.978-08:00

The chromatin, dispersed in the nucleus, is a set of filamentous DNA molecules associated to nuclear proteins called histones. Each DNA filament is a double helix of DNA and thus a chromosom

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-9043408847374705622013-02-27T03:04:00.004-08:002013-02-27T03:04:33.675-08:00

What are the substances that constitute the chromatin? The chromatin, dispersed in the nucleus, is a set of filamentous DNA molecules associated to nuclear proteins called histones. Each DNA filament is a double helix of DNA and thus a chromosome.

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-59068136211947722792013-02-27T03:03:00.001-08:002013-02-27T03:03:13.299-08:00

Within the cell nucleus the main structures are: the nucleolus, an optically dense region, spherical shaped, where there are concentrated ribosomal RNA (rRNA) associated to proteins (there may be more than one nucleolus in a nucleus); the chromatin, made of DNA molecules dispersed in the nuclear matrix during the cell interphase; the karyotecha, or nuclear membrane, the membrane that

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-9544242024455851012013-02-27T03:02:00.002-08:002013-02-27T03:02:40.229-08:00

This is an interesting problem of biological evolution. The most accepted hypothesis asserts that the more simple cell, the prokaryotic cell, appeared earlier in evolution than the more complex eukaryotic cell. The endosymbiotic hypothesis, for example, affirms that aerobic eukaryotic cells appeared from the mutualist ecological interaction between aerobic prokaryotes and primitive

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-51635515036973753222013-02-27T03:01:00.002-08:002013-02-27T03:01:39.130-08:00

Plasma membrane and cell wall are not the same thing. Plasma membrane, also called cell membrane, is the outer membrane common to all living cells and it is made of a phospholipid bilayer, embedded proteins and some appendedcarbohydrates. Because cell membranes are fragile, in some types of cells there are even outer structures that support and protect the membrane, like the cellulose

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-19302394530294277382013-02-27T03:00:00.004-08:002013-02-27T03:00:58.045-08:00

The main constituents of the plasma membrane are phospholipids, proteins and carbohydrates. The phospholipds, amphipathic molecules, are regularly organized in the membrane according to their polarity: two layers of phospholipids form the lipid bilayer with the polar part of the phospholipids pointing to the exterior of the layer and the non-polar phospholipid chains in the

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-24433995482881728032013-02-27T02:57:00.000-08:002013-02-27T02:57:06.420-08:00

Viruses are considered the only living beings that do not have cells. Viruses are constituted by genetic material (DNA or RNA) enwrapped by a protein capsule. They do not have membranes and cell organelles nor do they have self-metabolism.

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-75951056033112226852013-02-27T02:56:00.003-08:002013-02-27T02:56:26.503-08:00

Cell theory asserts that the cell is the constituent unit of living beings. Before the discovery of the cell, it was not recognized that living beings were made of building blocks like cells. The cell theory is one of the basic theories of Biology.

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-57194207651740384892013-02-27T02:56:00.000-08:002013-02-27T03:21:53.479-08:00

1. What is cell theory? Cell theory asserts that the cell is the constituent unit of living beings. Before the discovery of the cell, it was not recognized that living beings were made of building blocks like cells. The cell theory is one of the basic theories of Biology. 2. Are there living beings without cells? Viruses are considered the only living beings that do not have cells. Viruses

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-1318864269471308172012-05-31T03:07:00.000-07:002012-05-31T03:10:18.550-07:00

Pleiotropy refers to genes that can affect more than one character. A gene may make just one polypeptide, but that polypeptide can affect a number of different properties of an organism. The hemoglobin gene, sickled cells cause a breakdown of red blood cells and a higher likelihood of red blood cell clumping, which can block blood vessels and cause impaired mental function

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-90305914976858106762012-05-31T03:04:00.000-07:002012-05-31T03:10:05.895-07:00

Imagine reading an entire book, but then realizing that your glasses did not allow you to distinguish "g" from "q." What details did you miss?   Geneticists faced a similar problem with the recent discovery of a "sixth nucleotide" in the DNA alphabet. Two modifications of cytosine, one of the four bases that make up DNA, look almost the same but mean different things. But scientists

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-43918698297123744142012-05-30T02:55:00.001-07:002012-05-30T02:55:08.901-07:00

It appears that in some cases, high-density lipoprotein (HDL) cholesterol, the so-called "good" cholesterol, does not protect against heart diseases, and may even be harmful. A new study suggests a subclass of HDL that carries a particular protein is bad for the heart. Previous studies have shown that high levels of HDL cholesterol are strongly linked to low risk of heart disease

Unknownnoreply@blogger.comtag:blogger.com,1999:blog-5142461511979121342.post-52154885376521641212012-05-23T23:42:00.001-07:002012-05-23T23:42:42.487-07:00

Proteins are responsible for almost all biological functions. The cells of the human body continuously synthesize thousands of different proteins in the form of amino acid chains. In order to be biologically useful, these chains must fold into a complex three-dimensional pattern. When this difficult process goes wrong, it can lead to useless or even dangerous protein clumps. All cells, from

Unknownnoreply@blogger.com