NMAT Review: Biology Exam 2024 Questions and Answers Graded A+

hypertonic vs. hypotonic vs. isotonic solution - Hypertonic solution/environment - where the solution has a higher concentration of solutes than in the cell, so the cell has a higher water potential. This causes water from the cell to flow outwards, shrinking the cell/crenating it. Or in plant cells, plasmolyze it. Hypotonic solution/environment - where the solution has a lower concentration of solutes than in the cell, so the environment has the higher water potential. This causes a net movement of water into the cell, swell/lyse. Or in plant cells, become turgid. Isotonic solution/environment - where the solution and the cell have equal concentration of solutes and equal water potential. There is a zero net movement of water. Function of membrane proteins - -Cell-to-cell communication -cell-to-cell recognition site -attachment to the cytoskeleton & extracellular matrix (infrastructure) -across the membrane transportation --- small, polar uncharged molecules can pass (water, CO2) --- hydrophobic molecules can cross the lipid bilayer (hydrocarbons, O2) --- large, polar uncharged molecules can't pass through (sugars, proteins) --- ions can't pass without help from transport proteins/channels (H+, Na+, Cl-, K+) T-lymphocytes vs. B-lymphocytes - T-lymphocytes -- processed in the thymus that initiates the attack on foreign bodies. It's considered a part of the cell-mediated response B-lymphocytes -- released into the boodstream, it secretes antibodies which bind to the antigen and eventually destroy it. It's considered a part of the humoral immune response Point mutations: silent, missense, nonsense - Silent - causes no change in activity of the protein Missense - results in a change of the activity of the protein Nonsense - results to a protein shorter than usual/most likely becomes non-functional Frameshift mutations - A mutation where the whole frame of the genetic sequence is changed (most likely from an addition or subtraction of a nucleotide) Meristem - Zones of unspecialized cells whose sole function is to divide -Apical meristems produce primary growth (length). Three types: protoderm (epidermal tissue), procambrium (central vascular cylinder - stele), and ground meristem (ground tissue system) -Lateral meristem produces secondary growth (girth). Two types: vascular cambrium (produces secondary xylem & secondary phloem) and cork cambrium (produces cork cells and phelloderm) Classification of organisms - Kingdom, Phylum, Class, Order, Family, Genus, Species (Kings Play Chess On Fine Grain Sand) Dihybrid crossing - Blood types A, B, AB, and O - A - Has the antigen for A and the antibody for B B - Has the antigen for B and antibody for B AB - Has the antigen for A and B, no antibody; "universal recipient" O - No antigen, has antibody for A and B; "universal donor" embryonic development - 1) gametogenesis - making of sperm and egg 2) fertilization - sperm + egg = zygote 3) cleavage - sequence of cell division to become a multicellular organism, leading to blastula (hollow ball of cells) 4) gastrulation - leads to formation of germ layers (endoderm, mesoderm, ectoderm); pouch formed by gastrulation opens to the outside via the blastopore which eventually becomes the anus. 5) organogenesis - germ layers develop into different tissues and organism 6) growth and histological differentiation - cells of each organ begin to grow and differentiate to eventually become the necessary structure and function for that organ Germ layers - Ectoderm - eventually forms the skin and nervous system Mesoderm - eventually forms the bones, muscles, organs, and blood vessels Endoderm - eventually forms the digestive tract Sporophyte vs. gametophyte - Sporophyte - stage in plant life where they are in a diploid state Gametophyte - stage in plant life where they are in a haploid state, giving rise to the sex cells Ferns, pine trees, and common weeds are usually in a diploid state while mosses are dominantly haploid gametophytes. Mitosis stages - 1) Prophase - condensation of chromosomes (coiling) 2) Metaphase - alignment of the chromosomes at the equatorial plate 3) Anaphase - Pulling apart of the chromosomes to opposite sides; separation of sister chromatids 4) Telophase - mitotic apparatus formed during prophase is disassembled as 2 cells are formed (cytokinesis). Meiosis stages - Same stages as Mitosis but done twice in 2 parts: Meiosis I and Meiosis II Cardiac cycle - 1) Deoxygenated blood travels into right atrium and right ventricle via vena cava, out of the heart into the lungs. The now-oxygenated blood travels into the left atrium to the left ventricle and out the aorta to the rest of the body. The pacemaker of the heart is dependent on the sinoatrial node which sends an electrical pulse through the atria (resulting in atrial systole). This causes the atriventricular node to activate, sending impulses down to the bundle of His (resulting in ventricular systole)