MTTC Integrated Science Exam Questions & Answers

Observational recordings - Answer - should not be altered, erased, or whited-out to make corrections - drawing a single line through it Parts of a lab report - Answer 1. title 2. abstract - contain the hypothesis - include a control and one variable 3. introduction 4. methods 5. results 6. conclusion / summation Volumetric flask - Answer - used to accurately prepare a specific volume and concentration of solution Erlenmeyer flasks - Answer used for mixing, transporting, and reacting NOT appropriate for measuring Meniscus - Answer where the liquid measurement is read Graduated cylinders - Answer - precise measurements - more accurate than Erlenmeyer flasks or beakers Burette - Answer - glassware to accurately dispense liquid - has a stopcock and a tip Typical vs. Compound microscope - Answer - typical = 1 lens - compound = 3 lenses Chromatography - Answer set of laboratory techniques used to separate or analyze mixtures Diluting Acids - Answer - always add the concentrated acid solution to water Centrifuge - Answer - used to separate the components of a heterogeneous mixture by spinning it ex. separate blood cells and plasma - the heavier cells settle on the bottom of the test tube and the lighter plasma stays on top ex. salad spinner to dry lettuce Calorimetry - Answer used to determine the heat released or absorbed in a chemical reaction Titration - Answer helps determine the precise endpoint of a reaction Metric system - Answer - meter: length - liter = volume - gram = mass Graphs of independent vs dependent variable - Answer *independent variable = what is being manipulated is on the x-axis *dependent variable = the ones that may change as the independent variable changes is on the y-axis 5 skills developed from the National Science Education Standards - Answer 1. understand scientific concepts 2. appreciate "how we know" what we know in science 3. understand the nature of science 4. Develop the skills necessary to become independent inquirers about the natural world 5. develop the skills necessary to use the skills, abilities, and attitudes associated with science Scientific fact - Answer an objective and verifiable observation Scientific theory - Answer greater body of accepted knowledge, principles, or relationships that might explain why something happens Hypothesis - Answer - an educated guess that is not yet proven Law - Answer an explanation of events that always leads to the same outcome. Scientific Method - Answer 1. identify a problem or posing a question 2. formulating a hypothesis or an educated guess 3. conducting experiments or tests that will provide a basis to solve the problem or answer the question 4. observing the results of the test 5. drawing conclusions 6 abilities of K - 4 Students - Answer 1. able to ask questions about objects, organisms, and events in the environment 2. devise a simple investigation to answer a question 3. use tools such as magnifying glasses, rulers, and balances to gather data and make observations 4. use the gathered data and observations to provide an explanation 5. talk about, draw pictures, or use another method to communicate the results of an investigation and what they learned 6. understand the scientific inquiry 5 abilities of 5 - 8 Students - Answer 1. reformulate and clarify questions until they can be answered through scientific investigation 2. create and carry out a scientific investigation, interpret the data to provide explanations, and use further data to revise explanations 3. identify the tools necessary to gather and analyze data. Able to use computer hardware and software to store, organize and gather data 4. provide descriptors and explanations, create models, and make predictions based on the body of knowledge they possess 5. explain cause and effect relationships using explanations and data from experiments Greenhouse Gases - Answer - they are = ozone, carbon dioxide, water vapor, and methane - they trap infrared radiation that is reflected toward the atmosphere - without the greenhouse effect, the earth would be 30 degrees colder - the problem occurs bc human activity generates more greenhouse gases than necessary Ozone depletion - Answer - UV light breaks O2 into 2 very reactive oxygen atoms with unpaired electrons (free radicals) - 2 free radicals and another oxygen molecule form ozone (O3) Acid Rain - Answer - made up of water droplets for which the pH has been lowered due to atmospheric pollution - the common sources of the pollution are sulfur and nitrogen which are released through the burning of fossil fuels - can lead to the lowering the pH of lakes and ponds Cellphones & radiowaves - Answer - when speaking into a cell phone, the user's voice is converted into an electrical signal which is transmitted via radio waves to a cell phone tower, then to a satellite, then to a cell tower near the recipient, and then to the recipient's cell phone - the recipient's cell phone converts the digital signal back into an electrical signal GPS (global positioning system) - Answer - system of satellites that orbit the Earth and communicate with mobile devices to pinpoint the mobile device's position Ribosomes - Answer - involved in synthesizing proteins from amino acids Golgi apparatus - Answer involved in synthesizing materials such as proteins that are transported out of the cell - it is located near the nucleus and consists of layers of membrane Vacuoles - Answer sacs used for storage, digestion, and waste removal. *A plant has one large vacuole *Animal cells have small, sometimes numerous vacuoles Cytosol - Answer - liquid material in the cell - mostly water but contains some floating molecules cytoplasm - Answer refers to cytosol & the substructures (organelles) found within the plasma membrane Endoplasmic Reticulum - Answer 2 types: 1. rough (has ribosomes on the surface) 2. smooth (does not have ribosomes) - tubular network that comprises the transport system of a cell - fused to the nuclear membrane and extends through the cytoplasm to the cell membrane Chloroplast - Answer - in plants that plant cells use for photosynthesis - contain chlorophyll which has a green color - also contain yellow and red pigments, which give leaves the red and yellow colors in the fall as chloroplasts lose their chlorophyll Lysosome - Answer - digests proteins, lipids, and carbohydrates, and also transports undigested substances to the cell membrane so they can be removed RNA - Answer ribonucleic acid - consists of a long chain (polymer) of nucleotide units *Polymer = formed by repeating monomers *Monomer = small molecule that is a single compound that forms chemical bonds with other monomers to make a polymer - some RNA molecules have enzymatic activity E Eukaryotic vs. Prokaryotic Cells - Answer Eukaryotic = - animal/plant cell - have a nucleus - has membrane bound organelles (nucleus, endoplasmic reticulum, golgi body, lysosome, mitochondra) - divide by mitosis and are diploid - DNA richly studded with proteins Prokaryotic = - bacteria - do not have a nucleus - DNA in a nucleoid - has NO nucleus & NO membrane-bound organelles - divide by binary fission and are haploid *Similarities: - they both interact with the extracellular environment and use membrane-bound or membrane-associated proteins to achieve this - they both use diffusion and active transport to move materials in and out of their cells - both have flagella Plant vs. Animal Cells - Answer Plant: - Cell wall (cellulose) - Rectangular Shape - 1 very large central vacuole (90% of cell volume) - Chloroplasts - Flagella but no cilia - Carbohydrate stored as starch and also plant oils - photosynthesis in the chloroplasts Animal: - No cell wall (Only plasma membrane) - Round shape - 1 or more small vacuoles - mitochondria produce energy from food - No Chloroplasts - Flagella and cilia - Carbohydrates storage as glycogen and some stored as animal fat 4 functions of mitochondria - Answer 1) Production of cell energy 2) cell signaling (how communications are carried out within a cell) 3) cellular differentiation (the process whereby a nondifferntiated cell becomes transformed into a cell with a more specialized purpose) 4) cell cycle and growth regulation (process whereby the cell gets ready to reproduce and reproduces) Cellular Respiration - Answer - a set of metabolic reactions that convert chemical bonds into energy stored in the form of ATP - processes involved are glycolysis, the Krebs cycle, the electron transport chain, and chemiosmosis - 2 forms are aerobic and anaerobic - Aerobic: very common, and oxygen is the final electron acceptor & results in more ATP - Anaerobic: the final electron acceptor is not oxygen. Photosynthesis equation - Answer 6CO2 + 6H2O ------> C6H12O6 + 6O2 Active Transport Mechanism - Answer - exocytosis: expulsion or discharge of substances from a cell - endocytosis: ingestion of large particles into cell *Phagocytosis: ingestion of a particle *Pinocytosis: ingestion of a liquid - involves transferring substances from areas of lower concentration to areas of higher concentration - requires energy in the form of ATP Passive Transport Mechanisms - Answer - the movement of substances through membranes - diffusion: particles are transported from areas of higher concentration to areas of lower concentration -> when equilibrium is reached, diffusion stops - facilitated diffusion: specific molecules are transported by a specific carrier protein *Carrier protein = vary in terms of size, shape, and charge - osmosis: the diffusion of water through a semi-permeable membrane from an area of higher concentration to one of lower concentration - do not require energy from the cell Mitosis vs. Meiosis - Answer Mitosis: - the "daughter cell" is an exact replica of the parent cell Meisosis: - the daughter cells have different genetic coding than the parent cell - can only happen in specialized reproductive cells called gametes Chromatids - Answer - the DNA is replicated during cell division - chromatids are the two identical replicated pieces of chromosome that are joined at the centromere to form an "x" Gametes - Answer - cells used by organisms to reproduce sexually - gametes in humans are haploid (they contain only have of the organism's genetic information) = 23 chromosomes *this is bc 50% of DNA comes from each parent - other human cells contain all 46 chromosomes Haploid vs. diploid - Answer Haploid = there is one set of chromosomes (23) Diploid = there are 2 sets of chromosomes (one set from each parent) (46 chromosomes) Homeostasis - Answer the ability and tendency of an organism, cell, or body to adjust to environmental changes to maintain equilibrium Gene Expression - Answer - use of info. in a gene that result in a protein product *Transcription: synthesis of RNA (info. is provided by DNA) *Translation: decoding of mRNA used in the fabrication of protein; it occurs in transcription Meiosis - Answer *phases happen twice 1st phase: - chromosomes cross over, genetic material is exchanged, and tetrades of four chromatids are formed - the nuclear membrane dissolves - homologous pairs of chromatids are separated and travel to different poles - one cell division resulting in two cells 2nd phase: - both cell goes through a second division - the result is 4 daughter cells with different sets of chromosomes - the daughter cells are haploid (half the genetic material of the parent cell) *Meiosis encourages genetic diversity Mitosis - Answer interphase: - cell prepares for division by replicated its genetic and cytoplasmic material prophase: - chromatin thickens into chromosomes and the nuclear membrane disintegrates - pairs of centrioles move to opposite sides of the cell and spindle fibers begin to form metaphase: - spindle moves to the center of the cell and chromosome pairs align along the center of the spindle structure anaphase: - pairs of chromosomes, called sisters, begin to pull apart - when they are separated, they are called daughter chromosomes telophase: - spindle disintegrates, nuclear membranes reform - chromosomes revert to chromatin *in animal cells = the membrane is pinched *plant cells = a new cell wall begins to form Cytokinesis: - physical splitting of the cell (including the cytoplasm) into 2 cells Cancerous Cells - Answer - The DNA or gene structure is disrupted. - Abnormal numbers of chromosomes can develop. - They can have defective Krebs cycles, and get most of their energy from glycolysis. - They mainly produce energy without using oxygen. - They lack a blood vessel system and use amino acids to construct it. - the enzymes and hormones tend to be overactive or underactive Cell Theory - Answer - all living things are based up of cells - cells are the basic units of life - new cells are formed from pre-existing cells - all cells are similar *Matthias Schleiden and Theodor Schwann Anabolic Reaction - Answer - builds larger and more complex molecules (macromolecules) from smaller ones - require energy Catabolic Reaction - Answer - larger molecules are broken down into smaller, simpler molecules - release energy Chemiosmosis - Answer - a process by which energy is made available for ADP to form ATP - electrons move down the electron transport chain, the energy pumps protons to one side of a membrane - the equilibrium is disrupted at this point bc the concentration gradient where the protons have gathered is greater than the concentration gradient on the other side of the membrane - the protons diffuse through the membrane as a result -> the energy of this process fuels phosphorylation - enzymes act as catalysts by lowering the activation energy necessary for a reaction Glycolysis - Answer - glucose is converted into pyruvate and energy stored in ATP bonds is released Monosaccharides - Answer simple sugars (glucose, fructose) - have one monomer of sugar *Disaccharides have 2 Krebs Cycle (Citric Acid Cycle) - Answer - catabolic pathways in which the bonds of glucose are broken down and reformed into ATP - respiration process that uses oxygens and produces carbon dioxide, water, and ATP Electron Transport Chain - Answer - part of phosphorylation, where electrons are transported from enzyme to enzyme until they reach a final acceptor Positive and Negative Feedback Loops - Answer Positive feedback loops: - enhance or amplify changes - this tends to move a system away from its equilibrium state and make it more unstable. Negative feedbacks: - tend to dampen or buffer changes - this tends to hold a system to some equilibrium state making it more stable. DNA Structure - Answer - located in the cell nucleus and mitochondria - Francis Crick & James Watson formulated the double-helix model of DNA - Each base is attached to phosphate and to a sugar - 4 types of nitrogenous bases: *Adenine (A), Guanine (G), Cytosine (C), and Thymine (T) - A pairs with T - C pairs with G DNA Replication - Answer - steps in DNA replication are controlled by enzymes - the enzyme helicase instigates the deforming of hydrogen bonds between the bases to split the two strands - splitting A-T bonds and C-G bonds - each strand of DNA is transcribed by an mRNA - it copies the DNA onto itself, base by base, in a complementary manner - Uracil (U) replaces thymine (T) in the replication DNA polymerase - Answer - helps form the DNA strand by linking nucleotides DNA Ligase - Answer links the existing shorter strands into a longer strand Types of RNA - Answer - RNA acts as a helper to DNA *Ribosomal RNA (rRNA): - in the ribosomes *Messenger RNA (mRNA): - carries a copy of a strand of DNA and transports it from the nucleus to the cytoplasm *Transfer RNA (tRNA): - helps in the translation process and is found in the cytoplasm Differences between RNA & DNA - Answer RNA: - has a different sugar (ribose instead of deoxyribose sugar) - Nitrogenous bases are Adenine (A), Uracil (U), Guanine (G), and Cytosine (C) - single strand - supports the functions carried out by DNA; aids in gene expression, replication, and transportation DNA: - deoxyribose sugar - Nitrogenous bases are Adenine (A), Thymine (T), Guanine (G), and Cytosine (C) - double strand Codons - Answer - groups of 3 nucleotides on the mRNA - a codon has the code for a single amino acid - 64 codons and only 20 amino acids (more than one combination can be used to synthesize the necessary amino acids) Mutations - Answer - gene disorders are the result of DNA mutations - DNA mutations lead to unfavorable gene disorders, but provide genetic variability - the diversity can lead to increased survivability of a species - mutations can be: neutral, beneficial, or harmful - mutations can be hereditary tRNA Anticodons - Answer - the rRNA interprets the code again in a complementary fashion A -> U G -> C - ribosomes make proteins from amino acids by using the information on mRNA as a template for sequencing amino acids in a protein - tRNA carries amino acids that have attached to it to the ribosomes - the anticodons on the tRNA are a string of triplet bases that are complementary to the mRNA ex. Codon AAA on the mRNA -> anticodon UUU on the tRNA Translocation - Answer - genetic mutation in which once piece of a chromosome is transferred to another chromosome Mendel's Laws - Answer law of segregation (1st Law): - there are two alleles and that half of the total number of alleles are contributed by each parent organism law of independent assortment (2nd law): - traits are passed on randomly and re not influence by other traites Gene - Answer a portion of DNA that identifies how traits are expressed and passed on in an organism - all gene form the genotype of an individual Genotype - Answer - includes genes that may not be expressed, such as recessive genes Phenotype - Answer - the physical, visual manifestation of genes - determined by the basic genetic information and how genes have been affected by their environment Allele - Answer - a variation of a gene - aka a trait - determines the manifestation of a gene - this manifestation results in a specific physical apperance of some fact of an organism