Biology Midterm Review

Chapter 1 The Science of Biology What characteristics do all living things share? Made up of cells Based on universal genetic code Obtain and use materials and energy Grow and develop Reproduce Respond to environment Maintain stable internal environment (homeostasis) Evolve-change over time

Chapter 1 The Science of Biology Birds flying south is an example of which characteristic? Respond to environment A food web is an example of which characteristic? Living things need material and energy Define homeostasis. Organisms keep everything inside their bodies within certain limits What is the smallest object a biologist can study? The cell

Chapter 1 The Science of Biology Cells come in many shapes and sizes. What does this specialization allow for? Allows cells to perform different functions. Would a scientist who studies one branch of biology, like evolution, need to know about any other branches of biology? Yes: the branches of biology are interrelated. Define scientific hypothesis. Explanation based on observations that can be tested by experiment or further observations

Chapter 1 The Science of Biology How many variables are tested during a controlled experiment? A single variable Define theory. Unified set of hypothesis that may be revised or replaced

Chapter 2 The Chemistry of Life Name the three parts of an atom. Proton, neutron, and electrons Atomic number = number of protons Atomic mass = protons + neutrons When chemicals react with each other, atoms are not created or destroyed, they are rearranged.

Chapter 2 The Chemistry of Life 5 a. Carbohydrates- glucose (single sugar) b. Protein- amino acid c. DNA- nucleotide What two molecules are lipids made of? Fatty acids and glycerol What is the function of DNA? Store and transmit genetic information.

Chapter 2 The Chemistry of Life What is the function of proteins Help fight disease Control rate of reaction Move substances into/out of cell 9. Draw a graph for a reaction that absorbs energy

Chapter 2 The Chemistry of Life What is a catalyst? Speeds up chemical reaction by lowering the activation energy needed Are all catalysts enzymes? No enzymes are biological catalysts Is a catalyst “used up” during a chemical reaction? No –they can be used again and again What is an enzyme? A biological catalyst and they are proteins.

Chapter 2 The Chemistry of Life Enzymes work best at a specific temperature and pH. How do enzymes speed up a chemical reaction? By lowering activation energy What determines an enzymes function? Its shape. All enzymes have a unique shape. What is meant by the “lock and key” model? Shape of enzyme and substrate “fit” each other

Chapter 7 Cell Structure and Function List the levels of organization in a multicellular organism from simplest to most complex. Cell, tissue, organ, organ system. What invention made the discovery of cells possible? Microscope Prokaryotic cells lack a nucleus while eukaryotic cells enclose their DNA in a nucleus

Chapter 7 Cell Structure and Function What is the relationship between the nucleus and the cytoplasm? The nucleus is an organelle surrounded by the cytoplasm. What is the function of the cell membrane? Serves as cells boundary from its environment What is the function of the Golgi body? Modifies, sort and packages proteins and other materials for storage or release from cell.

Chapter 7 Cell Structure and Function 7. What is the function of the endoplasmic reticulum? Protein synthesis What is the function of the mitochondria? Power house—produce ATP What organelle is found in plants but not animals? Chloroplast Which two organelles are involved in energy conversion? Chloroplast and mitochondria

Chapter 7 Cell Structure and Function 11. Describe what happens during diffusion as equilibrium is reached? Molecules continue to move across the membrane in both directions at equal rates. What is osmosis? Diffusion of water a. Why does an animal cell burst if placed in fresh water? Water moves into cell due to osmosis.

Chapter 8 Photosynthesis Draw and label an ATP molecule. 2. What is the difference between ATP and ADP? ATP has 3 phosphates, while ADP has 2 phosphates

Chapter 8 Photosynthesis Define autotroph. Organism that makes its own food Define heterotroph. Organism that must obtain energy from external sources Write the overall equation for photosynthesis. 6 CO2 + 6 H2O C6H12O6 + 6 O2 What gas is given off? Oxygen The energy needed to power photosynthesis comes from the sun. Light

Chapter 8 Photosynthesis Is oxygen required for a candle to burn? Yes What would happen to sugar production if carbon dioxide is completely removed from a plants environment? No sugar would be produced. Draw a graph that represents the effect of temperature on the rate of photosynthesis.

Chapter 9 Cellular Respiration Write the overall equation for cellular respiration. C6H12O6 + 6 O2 6 CO2 + 6 H2O Cellular respiration occurs in mitochondria. Cellular respiration releases the energy in food molecules. Cellular respiration is called aerobic because it requires oxygen.

Chapter 9 Cellular Respiration How do animals get the energy they need? By breaking down food molecules gradually and capturing their chemical energy In what way are photosynthesis and cellular respiration opposite? Photosynthesis removes CO2 from the atmosphere, and cellular respiration puts it back. Glycolysis starts with what molecule? Glucose

Chapter 9 Cellular Respiration If oxygen is available, glycolysis is followed by the Krebs cycle. How many molecules of ATP are produced for each glucose molecule? 36 Where does lactic acid fermentation occur? In muscle cells

Chapter 10 Cell Growth, Division and Reproduction Cells need to be small so they can move needed materials in and waste products out DNA is replicated during S phase of the cell cycle. Draw and label a typical chromosome.

Chapter 10 Cell Growth, Division and Reproduction What is the difference between cell division and mitosis? Cell division is the process by which a cell divides into two daughter cells. Mitosis is the division of the nucleus. List the phases of mitosis in order. Prophase, Metaphase, Anaphase, Telophase During which phase of mitosis do the chromosomes line up in the middle? Metaphase

Chapter 10 Cell Growth, Division and Reproduction When are the chromosomes visible? During cell division Cancer is a disorder in which cells have lost the ability to control their growth rate. What are stem cells? Cells that have the potential to develop into other cell types.

Chapter 11 Introduction to Genetics Mendel’s principles apply to all organisms. Define alleles. Different forms of a gene A heterozygous tall plant is crossed with a short plant. What is the probability that an F1 plant will be tall? 50%

Chapter 11 Introduction to Genetics Define homozygous. Having two identical alleles for a particular trait Define heterozygous. Having two different alleles for a particular trait Tt x TT What are the phenotypes of the offspring? 100% Tall

Chapter 11 Introduction to Genetics If a plant is tt, what is true of its parents? Both parents contributed a recessive allele If an organism’s diploid number is 10, what is its haploid number? 5 Gametes are produced by the process of meiosis. Mitosis produces diploid (2n) cells while meiosis produces haploid (n).

Chapter 11 Introduction to Genetics Define crossing-over. Homologous chromosomes pair up and exchange DNA segments during meiosis I How is meiosis I different from mitosis? Meiosis I produces 2 haploid daughter cells, but mitosis produces 2 diploid daughter cells.