Living Environment Regents January 2008 Question 02
Tuesday, 21 April 2009 07:23
Option 2 – Cell membrane
The cell membrane (also called the plasma membrane, plasmalemma, or phospholipid bilayer) is the interface between the cellular machinery inside the cell and the fluid outside. It contains a wide variety of biological molecules, primarily proteins and lipids, which are involved in a vast array of cellular processes such as cell adhesion, ion channel conductance and cell signaling.
Option 1 – Ribosome: Ribosomes are complexes of RNA and protein that are found in all cells. Ribosomes from bacteria, archaea and eukaryotes, the three domains of life on Earth, have significantly different structure and RNA.
Option 3 – Nucleus: nucleus is referred to as the "control center", is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes.
Option 4 – Chloroplast: Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP.
Living Environment Regents January 2008 Question 03
Tuesday, 21 April 2009 09:08
Option 4 – Hormones and chemicals made by nerve cells
Cell-to-Cell communication is absolutely essential for multicellular organisms. Cells usually communicate by releasing chemical messengers targeted for cells that may not be immediately adjacent. Cell membranes contain specific protein-receptors, which bind & transmit extra-cellular signal molecules converting signals into specific cellular responses.
Cell signaling is part of a complex system of communication that governs basic cellular activities and coordinates cell actions. The ability of cells to perceive and correctly respond to their microenvironment is the basis of development, tissue repair, and immunity as well as normal tissue homeostasis.
Living Environment Regents January 2008 Question 04
Tuesday, 21 April 2009 09:15
Option 1 – type and order of amino acids
Proteins are very important molecules in our cells. They are involved in all cell functions. Each protein within the body has a specific function. Some proteins are involved in structural support, while others are involved in bodily movement, or in defense against germs.
Proteins vary in structure as well as function. They are constructed from a set of 20 amino acids and have distinct three-dimensional shapes. Below is a list of several types of proteins and their functions.
Antibodies - are specialized proteins involved in defending the body from antigens (foreign invaders). One way antibodies destroy antigens is by immobilizing them so that they can be destroyed by white blood cells. Contractile Proteins - are responsible for movement. These proteins are involved in muscle contraction and movement.
Enzymes - are proteins that facilitate biochemical reactions. They are often referred to as catalysts because they speed up chemical reactions. Hormonal Proteins - are messenger proteins which help to coordinate certain bodily activities. Examples include insulin, oxytocin, and somatotropin. Insulin regulates glucose metabolism by controlling the blood-sugar concentration.
Structural Proteins - are fibrous and stringy and provide support. Examples include keratin, collagen, and elastin. Keratins strengthen protective coverings such as hair, quills, feathers, horns, and beaks.
Storage Proteins - store amino acids. Examples include ovalbumin and casein. Ovalbumin is found in egg whites and casein is a milk-based protein.
Transport Proteins - are carrier proteins which move molecules from one place to another around the body. Examples include hemoglobin and cytochromes. Hemoglobin transports oxygen through the blood. Cytochromes operate in the electron transport chain as electron carrier proteins.
Living Environment Regents January 2008 Question 06
Tuesday, 21 April 2009 09:33
Option 3 – Organelles carry out functions similar to those of organs
In biology, an organ is a specialized structure that performs a specific function or group of functions. Organs are prominent in multicellular (an organism composed of many cells, which are to varying degrees integrated and independent) organisms.
An organelle is a specialized subunit within a cell that has a specific function, and is enclosed within its own lipid membrane. Organelles in unicellular (single cell) organisms are the equivalent of organs in multicellular organisms
Living Environment Regents January 2008 Question 08
Tuesday, 21 April 2009 10:06
Option 4 – coiled strands of genetic material
Chromosome is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. It is a microscopic, threadlike part of the cell that carries hereditary information in the form of genes. It is found in the nucleus of every cell. chromosome appears as a fibrous structure, called the chromonema, consisting of accumulations of chromatin, the dye-absorbing material. During nuclear division, when each chromosome splits, each of the duplicate chromosomes is called a chromatid. A certain number of chromosomes is characteristic of each species of plant and animal; e.g., the human has 46 chromosomes, the potato has 48, and the fruit fly Drosophila has 8.
Living Environment Regents January 2008 Question 30
Tuesday, 21 April 2009 12:38
Option 3 – A: Carbon Dioxide and Water; B: Glucose
Inorganic molecules are substances that don’t have carbon-hydrogen (C-H) bonds; generally simple and are not normally found in living things. Things like mineral, metals and salts would be considered inorganic molecules. In the above options carbon dioxide and water are inorganic molecules
Organic molecules, substances that contain carbon-hydrogen bonds, are found in living things. The major classes of organic molecule include carbohydrates, proteins, lipids and nucleic acids. Glucose is an organic molecule in the above diagram.
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