Diversified_Flashcards_for_Exam_Preparation
What does it mean when DNA is double-stranded?
It consists of two complementary strands of nucleotides.
What does it mean when DNA is antiparallel?
The two strands run in opposite directions (one 5’ to 3’, the other 3’ to 5’).
What is the difference between DNA and RNA?
DNA is double-stranded with deoxyribose sugar, and RNA is single-stranded with ribose sugar.
What is the central dogma?
DNA → RNA → Protein.
What are the steps of DNA replication?
- Helicase unwinds DNA. 2. Primase adds RNA primer. 3. DNA polymerase synthesizes DNA. 4. Ligase seals gaps.
What are the three modifications of eukaryotic RNA?
- 5’ Capping, 2. Poly-A Tail, 3. Splicing.
What is alternative splicing?
The rearrangement of exons to produce different proteins from the same gene.
What are the four protein structures?
Primary (sequence), Secondary (folds), Tertiary (3D shape), Quaternary (multiple subunits).
What is the function of tRNA in translation?
tRNA delivers amino acids to the ribosome by matching its anticodon to the mRNA codon.
What are the steps of translation?
- Initiation, 2. Elongation, 3. Termination.
What is the difference between transcription and translation?
Transcription: DNA → RNA. Translation: RNA → Protein.
What is the difference between phototrophs and chemotrophs?
Phototrophs use light energy, chemotrophs use chemical energy.
What is the difference between autotrophs and heterotrophs?
Autotrophs make their own food; heterotrophs consume organic material.
What are the first and second laws of thermodynamics?
1st: Energy cannot be created or destroyed. 2nd: Energy transformations increase entropy.
What are endergonic and exergonic reactions?
Endergonic requires energy; exergonic releases energy.
What is the overall equation for cellular respiration?
Glucose + Oxygen → Carbon Dioxide + Water + ATP.
What are the stages of cellular respiration?
- Glycolysis, 2. Pyruvate Oxidation, 3. Citric Acid Cycle, 4. Electron Transport Chain.
What is the role of oxygen in cellular respiration?
Oxygen is the final electron acceptor in the electron transport chain.
What is the overall equation for photosynthesis?
Carbon Dioxide + Water + Light Energy → Glucose + Oxygen.
What are the two sets of reactions in photosynthesis?
- Light-Dependent Reactions, 2. Calvin Cycle (Light-Independent Reactions).
What is the role of chlorophyll in photosynthesis?
Chlorophyll absorbs light, primarily blue and red wavelengths.
What are homologous chromosomes?
Chromosome pairs with the same genes but different alleles, one from each parent.
What are sister chromatids?
Identical copies of a chromosome, connected at the centromere.
What is the difference between mitosis and meiosis?
Mitosis creates 2 identical diploid cells; meiosis creates 4 diverse haploid cells.
What is cancer?
Uncontrolled cell growth due to mutations affecting the cell cycle.
What is PCR?
Polymerase Chain Reaction amplifies DNA using cycles of denaturation, annealing, and extension.
What is gel electrophoresis used for?
To separate DNA fragments based on size.
What are restriction enzymes?
Enzymes that cut DNA at specific sequences, used in genetic research.
What is a mutation?
A change in DNA sequence.
What are point mutations?
Single nucleotide changes, including silent, missense, and nonsense mutations.
What is the difference between genotype and phenotype?
Genotype is genetic makeup; phenotype is the observable trait.
What is the law of segregation?
Alleles separate during gamete formation.
What is the law of independent assortment?
Genes for different traits are inherited independently if they are on different chromosomes.
What is a Punnett square used for?
To predict the genotype and phenotype ratios of offspring.
What determines sex in humans?
The presence of XX (female) or XY (male) chromosomes.
What is the difference between single-gene and complex traits?
Single-gene traits are controlled by one gene; complex traits are influenced by multiple genes and the environment.
What is totipotency?
The ability of a cell (e.g., zygote) to form all cell types, including extraembryonic tissues.
What are pluripotent cells?
Cells that can form most cell types but not extraembryonic tissues.
What are multipotent cells?
Cells that can form limited cell types (e.g., blood cells from bone marrow).
What is natural selection?
The process where traits that improve survival and reproduction become more common.
What is genetic drift?
Random changes in allele frequencies, especially in small populations.
What is reproductive isolation?
Mechanisms that prevent species from interbreeding.
What is the difference between prezygotic and postzygotic isolation?
Prezygotic prevents fertilization; postzygotic occurs after fertilization and reduces hybrid viability or fertility.
What is allopatric speciation?
New species form due to geographic isolation.
What is sympatric speciation?
New species form in the same geographic area due to ecological or behavioral factors.
What are Okazaki fragments?
Short DNA fragments on the lagging strand during replication.
What is a missense mutation?
A mutation that changes one amino acid in a protein.
What is a nonsense mutation?
A mutation that introduces a stop codon, truncating the protein.
What is the role of helicase in DNA replication?
Helicase unwinds the DNA double helix.
What is the role of DNA polymerase?
It adds nucleotides to the growing DNA strand during replication.
What is the role of ligase in DNA replication?
It joins Okazaki fragments on the lagging strand.
What are examples of prezygotic isolating mechanisms?
Temporal, behavioral, mechanical, and habitat isolation.
What are examples of postzygotic isolating mechanisms?
Hybrid sterility and reduced hybrid viability.
What is the Calvin cycle?
The process in photosynthesis that fixes carbon dioxide to synthesize carbohydrates.
What is the main product of glycolysis?
Pyruvate, ATP, and NADH.
What happens during prophase of mitosis?
Chromosomes condense, and spindle fibers form.
What happens during metaphase of mitosis?
Chromosomes align at the cell’s equator.
What is the final electron acceptor in the electron transport chain?
Oxygen.
What are the inputs of the light-dependent reactions in photosynthesis?
Light, water, and ADP + Pi.
What are the outputs of the Calvin cycle?
Glucose, ADP, and NADP+.
What are stem cells?
Undifferentiated cells that can develop into specialized cell types.
What is crossing over?
The exchange of genetic material between homologous chromosomes during prophase I of meiosis.
What is independent assortment?
The random orientation of homologous chromosomes during metaphase I of meiosis.
What are nonhomologous chromosomes?
Chromosomes that do not pair during meiosis and contain different sets of genes.
What is a phylogenetic tree?
A diagram showing evolutionary relationships among species.
What is the Hardy-Weinberg principle?
A model that describes allele frequencies in a non-evolving population.
What are the five conditions for Hardy-Weinberg equilibrium?
No mutation, random mating, no natural selection, large population size, no gene flow.
What is genetic bottleneck?
A sudden reduction in population size, reducing genetic diversity.
What is gene flow?
The movement of alleles between populations, increasing genetic variation.
What is adaptive radiation?
The diversification of a single ancestral species into multiple new forms.
What is convergent evolution?
Unrelated species evolve similar traits due to similar environments.
What is divergent evolution?
Species with a common ancestor evolve different traits due to different environments.
What are homologous structures?
Structures in different species with a common ancestral origin.
What are analogous structures?
Structures with similar functions but different evolutionary origins.
What is a silent mutation?
A mutation that does not change the amino acid sequence of a protein.
What is binary fission?
Asexual reproduction in prokaryotes where the cell divides into two identical cells.
What is the role of spindle fibers in cell division?
They help separate chromosomes during mitosis and meiosis.
What is the difference between genotype frequency and allele frequency?
Genotype frequency is the proportion of specific genotypes; allele frequency is the proportion of specific alleles.
What is the relationship between genotype and phenotype?
Genotype determines the genetic makeup, while phenotype is the observable expression.
What is the difference between primary and secondary succession?
Primary succession occurs on bare rock; secondary occurs in areas where soil is intact.
What is stabilizing selection?
A type of natural selection that favors average traits.
What is directional selection?
A type of natural selection that favors one extreme trait.
What is disruptive selection?
A type of natural selection that favors both extreme traits.
What are the major differences between meiosis I and meiosis II?
Meiosis I separates homologous chromosomes; meiosis II separates sister chromatids.
