Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Genetics and Evolution
Genetics and evolution are foundational concepts in biology
Genetics studies the inheritance and variation of traits in living organisms
Evolution explains how species change over time through the process of natural selection
These concepts are important for understanding the diversity of life on Earth
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Key Terms
Allele
: Different versions of a gene
Genotype
: Genetic makeup of an organism
Phenotype
: Observable traits of an organism
Natural selection
: Process by which favorable traits are passed onto the next generation
Mutation
: Random changes in DNA sequence
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Gregor Mendel’s Laws of Inheritance
Mendel’s principles explain patterns of inheritance
Law of Segregation
: Alleles segregate during gamete formation
Law of Independent Assortment
: Alleles for different traits segregate independently during gamete formation
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Punnett Squares
Punnett squares are used to predict possible genotypes and phenotypes in offspring
It shows the possible combinations of alleles from both parents
Example
:
Parent 1 genotype: Aa
Parent 2 genotype: Aa
Possible offspring genotypes: AA, Aa, aa
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Genetic Disorders
Genetic disorders can result from mutations in genes
Examples
:
Cystic fibrosis
Huntington’s disease
Down syndrome
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
DNA Structure
DNA (deoxyribonucleic acid) is the genetic material in all living organisms
It has a double-helix structure composed of nucleotides
Nucleotides consist of a sugar, phosphate group, and nitrogenous base
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
DNA Replication
DNA replication is the process of copying DNA
It occurs during the S phase of the cell cycle
Enzymes called DNA polymerases add complementary nucleotides to form new strands
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Transcription
Transcription is the synthesis of RNA from a DNA template
It occurs in the nucleus
RNA polymerase binds to a DNA strand and creates a complementary RNA strand
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Translation
Translation is the process of protein synthesis from RNA
It occurs in the cytoplasm at ribosomes
Transfer RNA (tRNA) carries amino acids to the ribosome, and the ribosome assembles them into a protein
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Photosynthesis
Photosynthesis is the process by which plants convert sunlight into chemical energy
It occurs in the chloroplasts
Equations
:
Overall equation: 6CO2 + 6H2O + sunlight → C6H12O6 + 6O2
Light-dependent reactions: convert light energy to ATP and NADPH
Calvin cycle (light-independent reactions): convert CO2 to glucose
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Concepts Summary (Genetics and Evolution)
Genetics studies inheritance and variation of traits
Mendel’s laws explain patterns of inheritance
Punnett squares can predict offspring genotypes and phenotypes
Genetic disorders can result from mutations in genes
DNA structure consists of a double helix and nucleotides
DNA replication, transcription, and translation are key processes in genetics
Evolution explains how species change over time
Natural selection is the driving force of evolution
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Genetic Disorders
Genetic disorders can be inherited or caused by mutations
Examples
:
Cystic fibrosis: autosomal recessive disorder affecting the respiratory and digestive systems
Huntington’s disease: autosomal dominant disorder causing progressive degeneration of the nervous system
Down syndrome: chromosomal disorder resulting in intellectual disability and distinctive physical features
Genetic counseling and testing can help identify and manage genetic disorders
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
DNA Replication
DNA replication ensures accurate transmission of genetic information
Steps in DNA replication
:
Initiation: DNA helicase separates the DNA strands
Elongation: DNA polymerase adds complementary nucleotides to form new strands
Termination: DNA ligase seals any gaps in the newly synthesized strands
Replication occurs in multiple origins along the DNA molecule
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Transcription
Transcription is the process of synthesizing RNA from a DNA template
Steps in transcription
:
Initiation: RNA polymerase binds to the promoter region on DNA
Elongation: RNA polymerase adds complementary RNA nucleotides
Termination: RNA polymerase reaches a termination signal and detaches from DNA
Transcription produces different types of RNA, including mRNA, tRNA, and rRNA
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Translation
Translation is the process of protein synthesis from mRNA
Steps in translation
:
Initiation: mRNA binds to a ribosome, and tRNA brings the first amino acid
Elongation: tRNA carries amino acids to the ribosome, and the ribosome assembles them into a polypeptide chain
Termination: The ribosome reaches a stop codon, and the polypeptide is released
Codons on mRNA correspond to specific amino acids
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Photosynthesis - Light-Dependent Reactions
Light-dependent reactions occur in the thylakoid membrane of chloroplasts
Steps of light-dependent reactions
:
Light absorption: Pigments in photosystems capture light energy
Electron transport: Excited electrons move through the electron transport chain
ATP synthesis: ATP synthase generates ATP using the energy from the electron transport chain
Production of NADPH: Excited electrons reduce NADP+ to NADPH
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Photosynthesis - Calvin Cycle
The Calvin cycle occurs in the stroma of chloroplasts
Steps of the Calvin cycle
:
Carbon fixation: CO2 combines with a 5-carbon molecule, RuBP, to form a 6-carbon molecule
Reduction: ATP and NADPH are used to convert the 6-carbon molecule into G3P
Regeneration of RuBP: Some G3P molecules are used to regenerate the initial CO2 acceptor, RuBP
Glucose synthesis: G3P molecules can be used to produce glucose and other carbohydrates
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Factors Affecting Photosynthesis
Light intensity
: Higher light intensity increases the rate of photosynthesis until a saturation point is reached
Carbon dioxide concentration
: More CO2 leads to increased photosynthesis until CO2 levels become limiting
Temperature
: Within an optimal range, higher temperatures enhance photosynthesis, but extreme temperatures can damage enzymes involved
Water availability
: Sufficient water is necessary for the absorption and transport of minerals and the maintenance of turgor pressure
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Evolution by Natural Selection
Natural selection is the primary driving force behind evolution
The key components of natural selection include
:
Variation: Individuals within a population have different traits
Heritability: Traits can be inherited by offspring
Selection pressure: Certain traits provide an advantage in a particular environment
Differential reproduction: Individuals with advantageous traits have higher reproductive success
Adaptation: Over time, populations evolve traits that are better suited to their environment
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Mechanisms of Evolution
Besides natural selection, other mechanisms contribute to evolution
:
Genetic drift: Random changes in allele frequencies due to chance events in small populations
Gene flow: Movement of alleles between populations through migration
Mutation: Random changes in DNA sequences that introduce new genetic variation
Non-random mating: Sexual selection and assortative mating affect allele frequencies in populations
These mechanisms can lead to changes in a population’s gene pool over time
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Genetics and Evolution - Concepts Summary
Genetics studies inheritance and variation of traits
Mendel’s laws explain patterns of inheritance
Punnett squares can predict offspring genotypes and phenotypes
Genetic disorders can be inherited or caused by mutations
DNA replication, transcription, and translation are key processes in genetics
Evolution explains how species change over time
Natural selection is the driving force of evolution
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Evolution - Genetics and the Modern Synthesis
The modern synthesis combines genetics and evolutionary biology
It explains how genetic variations within populations can lead to evolutionary change
Mutation introduces new genetic variation
Gene flow can spread those variations through populations
Genetic drift and natural selection act on existing variations within populations
These mechanisms drive microevolution and can lead to the formation of new species (macroevolution)
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Evolutionary Evidence
Fossil record
: Shows the existence of extinct organisms and transitional forms
Homologous structures
: Similar structures in different species with a common ancestor
Comparative embryology
: Similarities in early development stages of different species
Molecular biology
: DNA and protein sequences reveal evolutionary relationships
Vestigial organs
: Functionless structures that were once useful in ancestors
Biogeography
: The distribution of species across different geographic regions
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Phylogenetic Trees
Phylogenetic trees represent the evolutionary relationships between species
Branches represent species or groups of species
Nodes represent common ancestors
The length of branches can indicate the amount of evolutionary change (time or genetic distance)
Patterns of branching can reveal evolutionary patterns and connections between species
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Mechanisms of Speciation
Speciation is the process by which new species arise
It can occur through two main mechanisms
:
Allopatric speciation: Geographic isolation leads to reproductive isolation and the formation of new species
Sympatric speciation: Speciation occurs in the absence of geographic isolation, often due to genetic changes or niche differentiation
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Hardy-Weinberg Principle
The Hardy-Weinberg principle describes a theoretical population in which allele frequencies remain constant over generations
The equation is
: p^2 + 2pq + q^2 = 1
p^2: Frequency of homozygous dominant individuals
2pq: Frequency of heterozygous individuals
q^2: Frequency of homozygous recessive individuals
p + q = 1: Sum of the frequencies of all alleles
This principle is used to study how evolutionary forces, such as natural selection and genetic drift, can change allele frequencies
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Cell Cycle
The cell cycle is the process by which cells divide and replicate
It consists of four main stages
:
G1 (Gap 1): Cell growth and normal metabolic activities
S (Synthesis): DNA replication occurs
G2 (Gap 2): Cell prepares for division and synthesizes necessary proteins
M (Mitosis): Cell division occurs, resulting in two daughter cells
The cell cycle is regulated by checkpoints to ensure proper division and replication
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Cell Division - Mitosis
Mitosis is the process by which cells divide and produce two genetically identical daughter cells
The stages of mitosis are
:
Prophase: Chromosomes condense, and the nuclear envelope breaks down
Metaphase: Chromosomes line up in the middle of the cell
Anaphase: Sister chromatids separate and move towards opposite poles
Telophase: Chromosomes decondense, and the nuclear envelope reforms
Cytokinesis: The cell membrane pinches in to divide the cytoplasm and organelles
Mitosis is important for growth, repair, and asexual reproduction
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Cell Division - Meiosis
Meiosis is the process by which cells divide and produce four genetically different daughter cells
It consists of two rounds of division (Meiosis I and Meiosis II)
Meiosis I
:
Prophase I: Homologous chromosomes pair up and undergo genetic recombination
Metaphase I: Homologous chromosomes line up in the middle of the cell
Anaphase I: Homologous chromosomes separate and move towards opposite poles
Telophase I: Chromosomes decondense, and the nuclear envelope reforms
Cytokinesis: The cell divides, resulting in two haploid cells
Meiosis II is similar to mitosis, resulting in four haploid daughter cells
Meiosis is important for sexual reproduction and creating genetic diversity
Genetics And Evolution Concepts Summary And Evolution Photosynthesis
Cell Division - Mitosis vs. Meiosis
Mitosis
:
Purpose: Growth, repair, and asexual reproduction
Number of divisions: One
Resulting cells: Two genetically identical diploid (2n) cells
Meiosis
:
Purpose: Sexual reproduction and creating genetic diversity
Number of divisions: Two
Resulting cells: Four genetically different haploid (n) cells
Both processes involve the separation of chromosomes, but their outcomes and purposes are different