bio final Flashcards
Mitosis
-makes body cells
-PMAT 1x
P: sister chromosomes condense
M: chromosomes line up in the MIDDLE
A: sister chromatids pulled AWAY to poles by spindles
T: new nuclei form on each side, make 2 new cells
CYTOKINESIS: ends with 2 identical diploid cells
Meiosis
-gametes (sperm/egg)
-PMAT 2x
P1: chromosome match with homologous pairs (from mom&dad), CROSSING OVER!
M1: pair at the MIDDLE
A1: pulled AWAY
T1: new nuclei form on each side to make 2 new cells
PMAT 2 same as mitosis
CYTOKINESIS: ends with 4 non-identical haploid cells
Cell Cycle & Cell Division
-Interphase:
- G1: cell grows/synthesizes proteins
-Synthesis Phase: DNA replicated -> 2 sister chromatids for each chromosome
-G2: cell continues to grow/prepare for division
-M Phase (Mitosis): cell division
Importance of Crossing Over & when it happens
When: Prophase I of meiosis
-create genetic variation w new combo of alleles
-evolution/adaptation
Binary Fission
-asexual reproduction in prokaryotic cells
-single-celled organism divides into 2 identical daughter cells
Complete Dominance
-heterozygotes have same phenotype as homozygous dominants
Incomplete Dominance
-heterozygotes have an appearance that is intermediate between the phenotypes of the two homozygotes (blend of color)
Co-Dominance
both alleles are expressed equally in the phenotype of the heterozygote (pink and purple colors visible)
Transcription (location, steps)
-FIRST
-Location: nucleus of cytoplasm
-Initiation: RNA polymerase binds
-Elongation: RNA polymerase unzips DNA and synthesizes complementary RNA strand
-Termination: RNA polymerase detaches and RNA strand released
Translation (location, steps)
-SECOND
Location: Ribosome (make protein)
Initiation: tRNA binds to start codon
Elongation: polypeptide chain of amino acids by reading mRNA codon
Termination: stop codon, polypeptide chain is released
Silent Mutation
-no change to amino acids, codes for same protein
Missense Mutation
-when there is a change in the amino acid sequence
-codes for different protein
Nonsense Mutation
-change an amino acid codon to a stop codon
Frame-Shift Mutation
-mutation by nucleotide deletions or insertions
CRISPER technology
-add, disrupt, or change the sequence of specific genes
GMO foods
-organisms that have acquired 1+ genes by artificial means
Gene Flow
-Exchange of genes between populations
Genetic Drift
-Random changes in allele frequency
Bottleneck Effect
-Drastic population size reduction impacts diversity
Founder Effect
-New populations started by a few individuals
Natural Selection
-Survival and reproduction of the fittest
Sexual Selection
-Traits that increase mating success
Directional Selection (graph)
-outcome of natural selection (1/3)
-Favors one extreme phenotype
-1large peak
Disruptive Selection (graph)
-outcome of natural selection (2/3)
-Favors two extreme phenotypes
-2 large peaks “M” shape
Stabilizing Selection (graph)
-outcome of natural selection (3/3)
- Favors intermediate phenotypes
-very tall/narrow graph
-majority of phenotype is only one type, not much of other phenotypes shown
Exponential Growth
-Rapid population increase; unsustainable long-term
-Represents ideal, unlimited growth
Logistic Growth
-Population stabilizes at carrying capacity
-Accounts for real-world resource limits and competition, making it more applicable to natural populations
Density-Dependent Factor
-population-limiting factor whose effects intensify as the population increases in density
-Competition, limited food supply. limited territory
Density-Independent Factor
-population-limiting factor whose intensity is unrelated to population density
-natural disasters: fires, flood, storms
Ecological Footprint
-Measure human impact on ecosystems
Biological Control
-Use natural predators or parasites to manage pests (e.g., ladybugs for aphid control)
Biodiversity
- The variety of life at genetic, species, and ecosystem levels
IMPORTANCE:
-Provides ecosystem goods, services, and psychological benefits
THREATS:
-Habitat loss, overharvesting, pollution, and climate change.
-Loss of keystone species disrupts ecosystems
EFFORTS:
-Establish protected areas.
-Reduce human impact through sustainable practices.
ETHIC:
-responsibility to prevent extinction
-Practical benefits for medicine, food, and ecosystem stability
