Biology Proctored Exam Penn Foster

Biology Proctored Exam Penn Foster Characteristics of living things Ans- -All are composed of cells -All obtain energy and use it to develop -Can sense changes in the environment and adjust in response to change -Exhibit modifications that represent adaptations to their environment Levels of Biological Organization Ans- atom, molecule, organelle, cell, tissue, organ, organ system, organism How are organisms classified? Ans- on the basis of their evolutionary/genetic relatedness What is the scientific method? What is it's importance in biological sciences? Ans- Process used to validate observations while minimizing observer bias It's goal is for research to be conduced in a fair, unbiased and repeatable manner. The best way to discover how and why the world works What is matter? Ans- Anything that has mass and takes up space What is an atom? Ans- smallest unit of matter that retains all the chemical properties of an element. They combine to form molecules which then form into a solid, gas or liquid What is the structure of an atom? Ans- Nucleus in the center that contains protons (positively charged) and neutrons (no charge). The outermost region is called an electron shell that contain the electrons (negatively charged) What is an ionic bond? Ans- A chemical bond that's formed when an atom transfers and electron to another Atom What is a covalent bond? Ans- Results when 2 atoms share electrons in order to have a completed outer shell What is a double covalent bond? Ans- Occurs when 2 atoms share 2 pairs of electroms In order to be an organic molecule it must contain what? Ans- Carbon and hydrogen What are the main groups of organic molecules that build cells and their parts? Ans- Carbohydrates, proteins, lipids, nucleic acid What are the properties of water? Ans- Its attraction to polar molecules. High-specific heat. High heat of vaporization. The lower density of ice. High polarity. Carbohydrates Ans- Broken down to glucose to provide energy. What are the different kinds of carbs? Ans- Glucose= monosaccharide that serves as blood sugar Sucrose= disaccharide which is table sugar Polysaccharides= include starch, which stores energy in plants Glycogen= stores energy in animals Cellulose= makes up the structure of plant cell walls Protein Ans- macromolecule that contains carbon, hydrogen, oxygen, and nitrogen; needed by the body for growth and repair Lipid Ans- Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen. Serve as a long term energy source Nucleic acid Ans- macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus Form DNA which acts to store genetic information What is the cell theory? Ans- All living organisms are made up of cells The cell is the smallest structural and functional unit of all living organisms All cells arise from pre-existing cells Ribosome Ans- Makes proteins Endoplasmic Reticulum Ans- A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another. Smooth ER Ans- Makes lipids Rough ER Ans- That portion of the endoplasmic reticulum studded with ribosomes. Golgi Apparatus Ans- Sorts and packs protein into vesicles and transports them Lysosome Ans- Digests food, bacteria and worn out organelles Vacuole Ans- Stores food, enzymes and other material Mitochondria Ans- Powerhouse of the cell- produces energy for growth, development and movement Nucleus Ans- A part of the cell containing DNA and RNA and responsible for growth and reproduction Cell wall Ans- A rigid structure that surrounds the cell membrane and provides support to the cell Explain the process of diffusion: Ans- Molecules move from an area of higher concentration to an area of lower concentration until the concentration of molecules is the same at both sites Explain the process of osmosis: Ans- Water moves from areas of low solute concentration to areas of high solute concentration Describe a basic enzymatic reaction: Ans- S+E= P+E E represents the enzyme catalyzing the reaction S is the substance being changed P is the product of the reaction What is an enzyme? Ans- Catalysts that increase the speed of a chemical reaction without undergoing any permanent chemical change What is the process of photosynthesis? Ans- -The process in which the Sun's energy is converted into chemical energy (occurs in chloroplasts). -Carbon dioxide and water are added -Sugar and oxygen are produced What is cellular respiration? Ans- Cellular respiration is the process that releases energy from food in the presence of oxygen. What is the cellular respiration equation? Ans- 6O2 + C6H12O6 -> 6CO2 + 6H2O + Energy What is glycolysis? Ans- "splitting sugars." yields two molecules of ATP. What is Krebs cycle? Ans- This term refers to a series of chemical reactions that involve the complete oxidation of acetyl CoA and produce 2 mol of ATP (energy) along with hydrogen and carbon, which combine with oxygen to form (H2O) and (CO2). What is the electron transport chain? Ans- Is a sequence of electron carrier molecules that shuttle electrons, down a series of reactions that release energy; used to make ATP. What is cellular reproduction? Ans- Process by which cells divide to form new cells Growth phase- cell duplicates its contents and DNA Cell Division- the cytoplasm and DNA of a parent cell are distribute to 2 daughter cells How many chromosomes do humans have? Ans- 46 (23 pairs) What is nondisjunction and when does it occur? Ans- Nondisjunction occurs when chromosomes do not separate properly during cell division. This can form a gamete with an extra chromosome or one missing part or all of a chromosome (aka monosomy or trisomy). OCCURS DURING ANAPHASE 1 & 2 What is the law of dominance? Ans- Mendel's 2nd law of inheritance - one gene usually expresses itself over the other (one gene is dominant over the other) What is the law of segregation? Ans- during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent What is the law of independent assortment? Ans- Genes for different traits are inherited independently of each other What is DNA biotechnology and what are some issues? Ans- Use of natural biological systems to create a product or achieve some other end desired by humans Issues: -People feel it goes against the laws of nature -People worry about the safety of it How can lack of genetic control lead to cancer? Ans- When someone has inherited an abnormal copy of a gene, their cells already start out with one mutation. This makes it easier for enough mutations to build up for a cell to become cancer G1 (Growth 1) Ans- Cell volume doubles and organelles replicate S phase (synthesis) Ans- DNA is replicated G2 phase Ans- cell produces proteins necessary for mitosis and then prepares to divide What are the stages of mitosis? Ans- prophase= chromosomes become visible as paired chromatids and the nuclear enveloped disappears metaphase= the chromosomes are aligned at the spindle equator midway between the spindle poles anaphase= sister chromatids separate and become daughter chromosomes- each pole receives a set of daughter chromosomes telophase= spindle disappears as new nuclear envelopes form around the daughter chromosomes- each nucleus contains the same number and kinds of chromosomes the original parent nucleus Describe the purpose of the cell cycle control system Ans- Series of checkpoints to make sure that everything is proceeding properly. Checkpoints delay development from one phase off the cycle to the next until everything that should happen in a particular phase has happened Explain the phases of the cell cycle control system: Ans- G1= cell can enter GO or under apoptosis if DNA is damaged beyond repair. If the cell cycle passes his checkpoint, the cell is committed to complete the cycle G2= the cell checks to make sure DNA has been replicated properly M Checkpoint= cell makes sure the chromosomes are properly aligned and ready to be partitioned to the daughter cells What is apoptosis? Ans- Programmed chemical process that causes a cell to self-destruct Serves the purpose of keeping the number of cells in the body roughly constant and removing cells with damaged DNA Explain the basics of mitosis Ans- Type of cell division in which one cell(the mother) divides to produce 2 new cells(the daughters) that are genetically identical to itself Somatic cells aids in the growth and development of an organism as well as in the replacement of old and injured cells - results in 2 daughter cells that are genetically identical Explain the basics of meiosis Ans- Type of cell division in which the number of chromosome is reduced in half from the diploid number (2n) to a haploid number (n). The result is 4 gametes: eggs in females and sperm in males Reproductive cells produces gametes for sexual reproduction - The gametes contain half the number of chromosomes as the parent cell What are the stages of meiosis I? Ans- Interphase: DNA in the cell is copied resulting in 2 identical full sets of chromosomes Prophase 1: the copied chromosomes condense into x shaped structure- each chromosome is composed of 2 sister chromatids Metaphase 1: chromosome pairs line up next to each other along the center of the cell Anaphase 1: pair of chromosomes are pulled apart, pull one chromosome to each pole Telophase 1: chromosomes complete their move to opposite poles of the cell- 2 nuclei form What are the stages of meiosis II? Ans- Prophase II: 2 daughter cells, each with 23 chromosomes - membrane around the nucleus in each daughter cell dissolves away releasing chromosomes Metaphase II: 2 daughter cells in chromosomes line up end-to-end along the equator of the cell Anaphase II: Sister chromatids are then pulled to opposite poles due to the action of the meiotic spindleseparated chromatids are now individual chromosomes Telophase II: Chromosomes complete their move to the opposite poles of the cell - Membrane forms around each set of chromosomes to create 2 new cell nuclei What is the structure and function of DNA? Ans- Long chain of repeating units called nucleotide that consist of 2 strands that spiral around each other in a structure called double helix Each contains a 5-carbon sugar, phosphate group, and one of found nitrogen bases adenine(A), guanine(G), Cytosine(C), thymine(T) Function is to store all the genetic information that an organism needs to develop, function and reproduce What is a purine? Ans- Adenine and Guanine What is a pyrimidine? Ans- thymine and cytosine What is the structure and function of RNA? Ans- A single-stranded molecule that consists of nucleotides arranged in a long chain Contains a 4-carbon sugar called ribose, phosphate groups and 4 nitrogen-containing bases- Adenine(A), Guanine(G), Cytosine(C), uracil(U) Functions to convert the information stored in DNA into proteins What is messenger RNA (mRNA)? Ans- Carries information coding for protein synthesis from DNA to the ribosomes of the cell What is transfer RNA (tRNA)? Ans- Caries the required amino acids from the cytoplasm to the ribosome for protein synthesis. Helps to arrange the amino acids into the proper sequence for the synthesis of proteins What is ribosomal RNA (rRNA)? Ans- RNA that becomes part of ribosomes (the main component of ribosomes) and catalyzes the bonding of amino acids What is a prokaryotic cell and what is the structure? Ans- No true nucleas as the DNA is coiled up in the region of the cytoplasm called the nucleotide Capsule: outer covering that protects the cell Cell Wall: Outer covering that protects the bacterial cell and gives it s