Search results
Nov 30, 2023 · Revision notes on 7.1.1 Key Terms in Genetics for the AQA A Level Biology syllabus, written by the Biology experts at Save My Exams.
- Apoptosis Definition
- Function of Apoptosis
- Examples of Apoptosis
- Apoptosis and Cancer
- Apoptosis Pathway
- When Does Apoptosis occur?
- Quiz
Apoptosis is a process that occurs in multicellular when a cell intentionally “decides” to die. This often occurs for the greater good of the whole organism, such as when the cell’s DNA has become damaged and it may become cancerous. Apoptosis is referred to as “programmed” cell death because it happens due to biochemical instructions in the cell’s...
Apoptosis is an important evolutionary adaptation because it allows organisms to destroy their own cells. At first glance, that may sound like a terrible idea. Why would you destroy part of yourself? Well, perhaps if that part of yourself had become dangerous to the rest, as in the case of cells with damaged DNA that could become cancerous. Apoptos...
From Tadpole to Frog
A spectacular example of this is found in frog tadpoles, which destroy and re-absorb entire body structures as they undergo their transformation into frogs. Cells from tadpole’s gills, fins, and tail are “told” to die by apoptosis signals as the tadpole matures. The raw materials of these dissembled cells become building materials and food for their new growing limbs.
Human Nervous System Development
During the early development of the human nervous system, huge numbers of cells die through apoptosis. Why should that be so? The truth is, scientists are not entirely sure why so much programmed cell death occurs in the developing nervous system. Some think it is because forming the correct connections is a complex and potentially difficult process for young neurons; and because maximum efficiency of the nervous system is definitely in the organism’s best interest. Nerves require huge amount...
Mouse Feet
During embryonic development, the feet of mice start out as flat, spade-shaped things. As development proceeds, the feet separate into five distinct toes by the process of – you guessed it – apoptosis! Cells that connect the toes die off in order to create the distinct gaps between them. This is an example of how programmed cell death can be used to shape useful structures and create useful features, in addition to getting rid of un-needed ones.
One primary function of apoptosis is to destroy cells that are dangerous to the rest of the organism. A common reason for apoptosis is when a cell recognizes that its DNA has been badly damaged. In these cases, the DNA damage triggers apoptosis pathways, ensuring that the cell cannot become a malignant cancer. However, clearly this process sometime...
There are two major types of apoptosis pathways, each of which illustrates an important point about how apoptosis is triggered and why it is useful. Both major pathways are illustrated in the graphic below. The steps are discussed in more detail in the following lists:
Apoptosis occurs when a cell’s existence is no longer useful to the organism. This can occur for a few reasons. If a cell has become badly stressed or damaged, it may commit apoptosis to prevent itself from becoming dangerous to the organism as a whole. Cells with DNA damage, for example, may become cancerous, so it is better for them to commit apo...
1. Which of the following would you NOT expect to trigger apoptosis? A. Damage to a cell’s DNA B. Long-term oxygen deprivation C. An organism moving to a new stage of its life cycle, rendering some cells obsolete D.None of the above 2. Which of the following might occur if a mutation made apoptosis impossible? A. The nervous system might not develo...
May 14, 2022 · Examples: The resorption of the tadpole tail at the time of its metamorphosis into a frog occurs by apoptosis. The formation of the fingers and toes of the fetus requires the removal, by apoptosis, of the tissue between them.
Problem: The abundance of each functional protein must be regulated. We can then start by posing subproblems: Let's take a moment, though, first to reload a couple of ideas. The process of gene expression requires multiple steps depending on what the fate of the final product will be.
Genetic drift is a change in allele frequency in a population, due to a random selection of certain genes. Oftentimes, mutations within the DNA can have no effect on the fitness of an organism. These changes in genetics can increase or decrease in a population, simply due to chance.
Dec 24, 2022 · Orthologs, or orthologous genes, are genes in different species that originated by vertical descent from a single gene of the last common ancestor. For instance, the plant Flu regulatory protein is present both in Arabidopsis (multicellular higher plant) and Chlamydomonas (single cell green algae).
In this article, we will give you an in-depth explanation of codominance, the difference between incomplete dominance and a codominant relationship, give you a few examples, and a practice problem to try out, so you have a better understanding of this unique relationship.
