Introduction to Living Things and Key Biological Concepts

Characteristics of Life

Essential traits defining living organisms.

Homeostasis

Maintaining stable internal conditions in organisms.

Metabolism

Chemical processes for energy use in organisms.

Heredity

Transmission of genetic traits to offspring.

Evolution

Change in species over time through adaptation.

CHONPS

Key elements: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur.

Proteins

Molecules made of amino acids, essential for structure.

Carbohydrates

Organic compounds for energy, includes sugars and starches.

Amino Acids

Building blocks of proteins, 20 types exist.

Cellulose

Plant fiber, important for structure and support.

Nucleic Acids

DNA and RNA, carriers of genetic information.

Lipids

Fats and oils, energy storage and membrane structure.

Enzymes

Proteins that catalyze biochemical reactions.

Heterotrophs

Organisms that consume others for energy.

Autotrophs

Organisms that produce their own food from sunlight.

Photosynthesis

Process converting sunlight into chemical energy.

Cellular Respiration

Process converting sugar and oxygen into ATP.

Fermentation

Anaerobic process producing energy without oxygen.

Prokaryotes

Single-celled organisms without a nucleus.

Eukaryotes

Organisms with cells containing a true nucleus.

Osmosis

Diffusion of water across a semipermeable membrane.

Concentration Gradient

Difference in solute concentration across a membrane.

Mitosis

Cell division resulting in two identical daughter cells.

Meiosis

Cell division producing gametes with half chromosome number.

Asexual Reproduction

Reproduction without the fusion of gametes.

Growth

Increase in cell number from fertilized egg.

Repair & Renewal

Replacement of cells due to damage or aging.

Homologous Chromosomes

Paired chromosomes with matching genes.

Diploid

Cell with two sets of chromosomes (2n).

Interphase

Phase where the cell prepares for division.

Mitosis

Process producing two identical daughter cells.

Zygote

Fertilized egg formed from sperm and egg.

Meiosis

Cell division reducing chromosome number by half.

Gametes

Reproductive cells (sperm and egg).

Genetic Diversity

Variation in genetic traits among offspring.

Fertilization

Union of sperm and egg to form zygote.

Chromosome Reduction

Halving chromosome number from 46 to 23.

Cell Cycle

Sequence of phases in cell division process.

Mitosis

Single division producing genetically identical daughter cells.

Meiosis

Two divisions producing genetically different gametes.

Haploid

Cell with one set of chromosomes (1n).

Ecosystem

Natural unit of living and non-living interactions.

Biotic factors

Living components of an ecosystem.

Abiotic factors

Non-living components like water and air.

Population density

Number of individuals per area.

Exponential growth

Rapid population increase in J-shaped curve.

Logistical growth

Population growth with carrying capacity in S-shaped curve.

Carrying capacity

Maximum population an environment can support.

Producers

Autotrophs that create their own food.

Consumers

Heterotrophs that eat producers for energy.

Primary consumers

Herbivores that eat plants.

Secondary consumers

Carnivores that eat herbivores.

Omnivores

Organisms that eat both plants and animals.

Decomposers

Break down dead matter, recycling nutrients.

Food chain

Linear sequence showing energy transfer between organisms.

Food web

Complex network of interconnected food chains.

Energy flow

Energy moves unidirectionally from sun to consumers.

Carbon-Dioxide-Oxygen Cycle

Cycle of gas exchange between plants and animals.

Major land biomes

Distinct ecological areas like tundra and rainforest.

Tundra

Cold biome with permafrost and low vegetation.

Temperate Deciduous Forest

Moderate climate with trees that shed leaves.

Tropical Rainforest

High biodiversity, warm climate, and heavy rainfall.

Desert

Hot, dry biome with drought-resistant plants.

Water cycle

Process of evaporation, condensation, precipitation, transpiration.

Nitrogen cycle

Conversion of nitrogen gas into usable nitrates.

Succession

Gradual ecosystem development to a stable community.

Pioneer species

First organisms to colonize barren areas.

Climax community

Mature, stable ecosystem at succession's end.

Primary succession

Occurs on previously uninhabited surfaces like rock.

Secondary succession

Reestablishment in disrupted areas with existing soil.

Non-renewable resources

Resources that cannot be quickly replaced.

Renewable resources

Resources that can be replenished naturally.

Greenhouse effect

Heat trapping by Earth's atmosphere.

Global warming

Increase in Earth's temperature due to CO2.

Genetics

Study of heredity and trait variation.

Trait

Inherited characteristic of an organism.

Gene

DNA segment determining specific traits.

DNA

Molecule containing genetic information in cells.

Nucleotide

Building block of DNA, includes base and sugar.

Adenine

Nitrogen base pairing with thymine in DNA.

Guanine

Nitrogen base pairing with cytosine in DNA.

DNA replication

Process of DNA self-duplication.

RNA

Single-stranded nucleic acid involved in protein synthesis.

mRNA

Carries genetic information from DNA to ribosomes.

tRNA

Transfers amino acids during protein synthesis.

DNA transcription

Synthesis of mRNA from DNA in the nucleus.

DNA translation

Process of synthesizing proteins from mRNA.

Mendelian genetics

Study of inheritance patterns established by Mendel.

Alleles

Different forms of the same gene.

Law of Dominance

One allele is expressed over another in traits.

Law of Segregation

Alleles separate during meiosis for fertilization.

Probability

Likelihood of a specific genetic outcome.

Punnet Square

Chart showing possible gamete combinations.

Incomplete dominance

Heterozygous phenotype is a blend of traits.

Codominance

Both alleles are fully expressed in phenotype.

Linked genes

Genes inherited together due to proximity on chromosomes.

Sex-linked genes

Genes located on sex chromosomes, often X-linked.

Nondisjunction

Failure of chromosomes to separate properly during meiosis.

Aneuploidy

Abnormal number of chromosomes in a cell.

Trisomic

Condition with three copies of a chromosome.