NLN-PAX Science exam with 100% correct answers 2024 latest update

Cell the smallest living unit and the basic unit of function and structure for all living things. Living cells average approx. 60% water and vary in size and shape. For example, a red blood cell is disk shaped, whereas nerve cells can be very long and have extensions on their main body. Cells also vary in terms of their roles they play in the body. Despite their differences, cells have a number of common features and functions. Nucleus contains the genetic information, or DNA, and controls the activities of the cell. Brainpower Read More Plasma (cell) membrane is what is known as a semipermeable membrane that separates the contents of the cell from the surrounding fluid (interstitial fluid) Interstitial fluid contains substances such as amino acids, sugars, fatty acids, hormones, neurotransmitters, and salts. Semipermeable membrane refers to the selective nature of the plasma membrane. It contains pores and channels that allow only particles of the right size or the right chemical nature to pass through. Also, the plasma membrane contains receptors that bind with specific substances. Thus, it only allows for special entry or signals the cell to perform a certain activity. Cytoplasm is the fluid matrix found between the plasma membrane and the nucleus that acts as scaffolding for the organelles. Organelles (little organs) are specialized units in the cell that per form certain functions. Mitochondria are the locations for cellular respiration, that is, the conversion of food to energy at the cellular level. The site of energy production and of most of its ATP. ATP (adenosine triphosphate) the chemical the cell uses to store and transfer energy within itself. Ribosomes are the sites of protein synthesis in the cell. Some ribosomes float freely, whereas others are attached to the endoplasmic reticulum. Endoplasmic reticulum (ER) Ribosomes are attached. Serves as a means for transport within the cell and is made up of many channels. Rough endoplasmic reticulum named for the fact that it has ribosomes on its surface, serves to store and deliver the proteins made by the attached ribosomes. Smooth ER is free of ribosomes and is found in a variety of cells. It performs varying functions in different cells, including the storage of enzymes and minerals and the folding of proteins, among other things. It is thought to be involved in the detoxification of chemicals and the metabolism of fats. Golgi complex modifies and packages proteins destined for use in the cell or for export from the cell. Lysosomes are sacs that contain strong digestive enzymes. These sacs are responsible for digesting cell structures that are no longer living or that are malfunctioning, and for digesting waste. Cell wall only plant Only plant cells have them. It is responsible for the protection of the cell, the maintenance of the shape, and water balance. Chloroplasts contain chlorophyll, which is necessary for photosynthesis. Vacuoles plant cells also often large ones. Which are compartments in the cytoplasm that act as places for secretion, excretion, and storage. Chromatin DNA is in this loosely structured form when it is not dividing Chromosomes DNA is seen in condensed rod-shaped bodies when the cell is dividing Mitosis When cells divide, the appropriate amount of genetic material must be passed on to the new, or so-called daughter, cells. In somatic (non reproductive) cells, the new cells are identical copies of the parent cells. This is achieved by a doubling of the chromosomes prior to division. It is useful in the growth and repair of our bodies. Mitosis occurs in both plant and animal cells, although the process is slightly different. Zygote the cell created by the union of a sperm and egg contains a full set of chromosomes, half from each parent. Meiosis Another type of division takes place in the production of gametes (reproductive cells). It contains half of the normal number of chromosomes. It consists first of doubling of chromosomes and then two subsequent divisions. Thus the products are four daughter cells, each with half the normal number of chromosomes. Muscle tissue skeletal, cardiac, and smooth Epithelial tissue skin, the lining of organs Nervous tissue neurons Connective tissue cartilage, blood, fat, bone Organ performs a specialized function in the body. Organ system made up of a number of organs working together to carry out a major function. For examples, the circulatory system includes many organs, such as the heart, blood vessels, spleen, tonsils, and lymph nodes. These organs work together to circulate and deliver necessary products throughout the body. Organism the highest level of organization such as the human body Evolution is a theory regarding the processes that have produced the biological diversity we see today. Charles Darwin in 1859 published ON THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION evidence for evolution. Darwin's two main arguments were that 1. the present species evolved from ancestral ones and 2. Natural selection the process by which the traits that promote or enhance an organism's ability to survive and reproduce are passed on to following generations. Adaptation For natural selection to occur, organisms must have variations, some of which give the individuals having them an advantage in the struggle for survival. The struggle for survival occurs because each generation of a species produces more offspring than can survive. In this struggle, the individuals best suited to their environment survive ("survival of the fittest") and pass on the traits to their offspring Fossil record consists of remnants or traces of organisms from past geologic ages. Fossils that have been dated show a timeline for the appearance of different vertebrates in the following order: fish then amphibians, then reptiles, and finally mammals and birds Vertebrates animals with backbones Biogeography the geographical distribution of plants and animals Comparative anatomy the comparison of organisms' structures Comparative embryology the comparison of organisms' embryos