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Hydrogen Bonding

A weak attraction between slightly positive hydrogen atoms and slightly negative oxygen or nitrogen atoms, crucial for water cohesion and DNA stability.

Cohesion and Adhesion

Cohesion is water's ability to stick to itself, while adhesion is its ability to stick to other surfaces, vital for water transport in plants.

pH Scale

Measures the concentration of hydrogen ions (H⁺) in a solution, where low pH indicates acidity and can affect enzyme denaturation.

Dehydration Synthesis

Process of removing water to build polymers, essential in digestion and formation of macromolecules.

Hydrolysis

Process of adding water to break down polymers, fundamental in digestion and biomolecule breakdown.

Structure Determines Function

The shape of a molecule directly relates to its function, such as an enzyme's active site shape affecting substrate binding.

Selective Permeability

Cell membranes allow certain substances to pass while blocking others, maintaining homeostasis.

Diffusion

Molecules move from high to low concentration without energy use, essential for gas exchange.

Osmosis

Specific diffusion of water across a membrane towards higher solute concentration.

Active Transport Mechanisms

Requires energy to move substances against their concentration gradient, exemplified by the sodium-potassium pump.

Fluid Mosaic Model

Describes the cell membrane as a flexible structure with embedded proteins for transport and signaling.

Surface Area-to-Volume Ratio

As a cell grows, volume increases faster than surface area, limiting size and affecting efficiency of material exchange.

Cellular Specialization

Different cell types have structures that optimize functions, like muscle cells having more mitochondria for energy.

ATP (Adenosine Triphosphate)

Primary energy carrier in cells, releasing energy when converted to ADP.

Enzymatic Function

Enzymes are biological catalysts that speed up reactions by lowering activation energy.

Activation Energy

Minimum energy required to start a chemical reaction, facilitated by enzymes lowering this threshold.

Photosynthesis Overview

Process converting light energy into chemical energy in glucose, involving light-dependent reactions and the Calvin cycle.

Cellular Respiration

Metabolic process breaking down glucose to produce ATP, utilizing oxygen as the final electron acceptor.

Electron Transport Chain (ETC)

Series of protein complexes in mitochondria transferring electrons, creating a proton gradient for ATP synthesis.

Role of NADH and FADH2

Electron carriers transporting electrons to the ETC for ATP synthesis.

Anaerobic vs. Aerobic Respiration

Anaerobic occurs without oxygen, yielding less ATP, while aerobic is more efficient in ATP production.

Signal Transduction Pathways

Involve molecular events triggered by ligand binding to receptors, amplifying the signal within the cell.

Ligands and Receptors

Ligands are signaling molecules that bind to receptors, initiating cellular responses.

Phosphorylation Cascade

Series of events where proteins activate each other by adding phosphate groups, amplifying the signal.

Feedback Inhibition

Regulatory mechanism preventing overproduction of a product by inhibiting pathways when sufficient levels are reached.

Apoptosis

Programmed cell death, crucial for development and preventing cancer.

Mitosis

Process resulting in two identical daughter cells, essential for growth and repair.

Phases of the Cell Cycle

Consists of G1, S, G2, and M phases, each crucial for proper cell division.

Cyclins and CDKs

Proteins that regulate the cell cycle, ensuring timely progression.

Cancer and the Cell Cycle

Arises from checkpoint failure, leading to uncontrolled cell division.

Role of Tumor Suppressors

Proteins that halt the cell cycle in response to DNA damage, promoting repair or apoptosis.

Oncogenes

Mutated genes that promote uncontrolled cell division when overexpressed.

Alleles

Different versions of a gene that can result in variations in traits.

Genotype vs. Phenotype

Genotype is the genetic makeup, while phenotype is the observable expression of those genes.

Law of Segregation

Each parent contributes one allele for each gene during meiosis, leading to genetic variety.

Independent Assortment

Genes for different traits segregate independently during gamete formation.

Crossing Over

Homologous chromosomes exchange genetic material during meiosis, increasing diversity.

Mutations

Changes in DNA sequence, potentially leading to new traits; can be harmful, neutral, or beneficial.

Natural Selection

Process where individuals with advantageous traits are more likely to survive and reproduce.

Fitness

An organism's ability to survive and reproduce, affecting trait frequency in a population.

Hardy-Weinberg Equilibrium

Describes a non-evolving population with conditions including no mutations and random mating.

Adaptation

Inherited traits that enhance fitness in an environment, leading to evolutionary changes.

Speciation

Process through which new species arise, often through geographic or reproductive isolation.

Ecosystem Dynamics

How populations interact with their environments, including carrying capacity and trophic levels.

Trophic Levels

Hierarchical levels in an ecosystem where energy transfer occurs from producers to consumers.

Biogeochemical Cycles

Recycling of nutrients through ecosystems, highlighting the interconnectedness of life.

Density-Dependent Factors

Factors that impact population growth more as density increases, such as competition.

Human Impact on Ecosystems

Effects of human activities on biodiversity and ecosystem health.

Conservation Strategies

Approaches to preserve biodiversity and promote sustainable ecosystem management.