GCSE AQA Combined Science Biology Paper 1

Gene - answer-a segment of DNA that determines characteristics of your body How many chromosomes do humans have? - answer-46 (23 pairs) How many chromosomes do gametes (sex cells) have? - answer-23 Mitosis - answer-The process of cell division, resulting in two identical cells The cell cycle - answer-The cycle of your body's cells dividing in a series of stages How long does the cell cycle take? - answer-Anywhere from 24 hours to years (depending on the organisms stage of life) Cell division in organisms - answer-Pre-born baby- quick and constant Child afterbirth- Fairly rapid End of Puberty and Adulthood- slows drastically Stage 1- Cell Cycle - answer--Longest stage -Grows bigger -Increased mass -Duplicate their DNA -Increase number of ribosomes, mitochondria, etc. for cell divide Stage 2- Cell Cycle - answer--Mitosis occurs -Organelles get pulled apart and nucleus splits Stage 3- Cell Cycle - answer--Cytoplasm and Cell membrane split -Two identical daughter cells Cloning - answer-Producing identical offspring Zygote - answer-A fused egg and sperm cell embryonic stem cells - answer-Inner cells of the embryo Embryo - answer-One half of the zygote adult stem cells - answer-An undifferentiated cell of any organism that can rise to many more cells of the same type Problems with embryonic stem cells - answer--Human rights debate -Slow, expensive, unpredictable -Possibly cause cancer -Potentially infected with viruses Therapeutic cloning - answer-research using cells from an adult to produce a cloned embryo of themselves Stem call research could possibly treat: - answer--Spinal cord injuries -Diabetes -Eyesight -Heart damage -Damaged bone and cartilage Tissue - answer-A group of similar cells that perform the same function. Organs - answer-Groups of tissues that work together to perform a specific function or related functions Organ system - answer-group of organs that work together to perform a specific function Organ Systems in our body - answer-Digestive system, respiratory system, and the circulatory system Levels of organization (small to large) - answer-cell, tissue, organ, organ system, organism Digestive system - answer-body system the breaks down food and absorbs nutrients (digestion occurs) Enzymes - answer-break down large molecules for digestion to occur Small intestine - answer-absorption of molecules into your blood Function of muscular walls of the small intestine - answer-Squeeze undigested food into your large intestine Liver - answer-produces bile