Biology SAT 2024 /2025 questions and correctly written answers well explained year 2024 / 2025 graded A+

Biology SAT 2024 /2025 questions and correctly written answers well explained year 2024 / 2025 graded A+ "nine plus two" - ANSWER -cilia and flagella consist of nine pairs of microtubules arranged in a ring around 2 single microtubules arranged in the center Photosynthesis Formula - ANSWER -overall reduction reaction bc carbon in CO2 is gaining electrons from hydrogen in H2O Photosynthetic pigments - ANSWER -absorb light energy and use it to carry out photosynthesis phoylysis - ANSWER -during light dependent reaction where water is ripped apart to provide electrons to replace those lost by chlorophyll a. O2 is released phycobi lins - ANSWER -red phtosynethetic pigment and found in red algae Pigments - ANSWER -substances that absorb light in the visible spectrum Pineal - ANSWER --in brain 1. Melatonin - involved in biorhythms Pinocytosis - ANSWER -cell drinking, uptake of large dis solved molecules pioneer organisms - ANSWER -1st to inhabit, lichens (symbiont of algae and fungi) plasma cells - ANSWER -fight antigens in what is called primary immune response. don't live long plasmolysis - ANSWER -cell shrinking due to loss of water in a hypertonic solution Plastids - ANSWER -have a double membrane and are found in plants and algae. 1. chloroplasts - green bc they contain chlorophyll. sites of photosynthesis. inner membrane forms a series of structure called grana. grana lies in stroma . contain only genetic info and can self replicate 2. leucoplasts - colorless and store starch. found in roots, like turnips, or in tubers like potatoes 3. chromoplast - store carotenoid pigments responsible for red -orange -yellow coloring in flowers, carro ts, autumn trees Platyhelminthes (flatworms and tapeworms) - ANSWER --simplest animals with bilateral symmetry -ectoderm, endoderm, and mesoderm -digestive cavity has only 1 opening -solid body -no room for true digestive or respiratory systems Platyhelminthes (planaria) excretion - ANSWER -structure: flame cells waste: ammonia point mutation - ANSWER -simplest mutation. base pair substitution where one nucleotide converts to another polar covalent bond - ANSWER -electrons shared unequally, formed between any 2 atoms that are unalike polar -polar attraction - ANSWER -when 2 or more atoms form a bond resulting the entire molecule is wither polar (unbalanced) or nonpolar (balanced). stronger attractions b/w polar than nonpolar bc negative end of one p olar molecule attracts the positive end of another Pollination and Fertilization in Angiosperm - ANSWER -1. One pollen grain containing 3 haploid nuclei (one tube nucleus and 2 sperm nuclei) lands on sticky stigma of flower 2. Pollen grain absorbs moisture s and germinates into pollen tube that burrows into the ovary 3. Once inside, 2 sperm nuclei enter through the microphyll 4. One sperm fertilizes and becomes the egg (2n) 5. Other sperm nucleus fertilizes the 2 polar bodies and become (3n) ENDOSPERM or cot yledon that is food 6. Ovule becomes seed, ripened ovary becomes fruit polygenic inheritance - ANSWER -one phenotype controlled by many genes ex: hair or skin color polymerase chain reaction - ANSWER -cell free automated technique where one piece of DNA is rapidly copied/amplified polyploid - ANSWER -organism with more than 3 sets of chromosomes. results from nondisjunsction EX: breed plants to be polyploid so they'll produce more fruit polysaccharides - ANSWER -polymers of carbohydrates; form as many monos accharides are joined together by dehydration synthesis ex: cellulose - found in plants, make up plant cell walls starch - found in plants, the way plants store carbohydrates chitin - found in animals and mushrooms, makes up the exoskeleton in arthropods and cell walls in mushrooms glycogen - found in animals, "animal starch", used to store carbohydrates in liver and skeletal muscles population - ANSWER -all members of species in one area population characteristics - ANSWER -size, density, age distribution, death rate Porifera (Sponges) - ANSWER --no symmetry -no nerve or muscle tissue -sessile -filter nutrients from H2O drawn into a central cavity -consists of only 2 cell layers: ectoderm and endoderm connected by noncellular mesoglea -have specialized cells but not true tissues/organs -fragmentation -hermaphrodites Positive vs. Negative Feedback - ANSWER -Positive EX: -oxytocin, ethylene