MCAS Review Biology

DNA Structure

Made of nucleotide building blocks, double helix with sugar-phosphate sides and nitrogen base pairs forming rungs (A-T, C-G).

Gene Expression

Involves DNA → mRNA → Protein stages, with three types of RNA:mRNA, rRNA, tRNA.

Transcription

Process of making an RNA copy of DNA (DNA → mRNA) in the nucleus.

Translation

Building a protein from mRNA sequence of amino acids in the cytoplasm.

DNA Replication

Process resulting in a new DNA strand, an exact copy of the original DNA.

Genetic Code

Translation of mRNA codons into amino acids using a codon chart.

Mutations

Changes in DNA or RNA sequence, affecting protein structure and function.

Digestive System

Structures and functions of organs like mouth, esophagus, stomach, small intestine, large intestine, rectum, pancreas.

Circulatory System

Components like heart, arteries, capillaries, veins, red blood cells, and their functions.

Respiratory System

Structures such as nose, pharynx, larynx, trachea, lungs, alveoli, and their functions in gas exchange.

Excretory System

Organs like skin, lungs, liver, kidneys, and their roles in waste removal and maintaining body balance.

Nervous and Endocrine Systems

Structures like brain, spinal cord, glands, and functions of monitoring and regulating body responses.

Homeostasis

Maintaining stable internal conditions through negative feedback mechanisms and small-scale cellular processes.

Cell-Level Homeostasis

Involves lysosomes, plasma membranes, proteins, and different types of passive and active transport.

Cell Cycle

Includes S Phase for DNA replication, mitosis for chromosome separation, and separation of cell contents for growth and repair.

Complementary bases

Bases that pair up following base pairing rules (A pairs with T; C pairs with G)

DNA replication

Process where two identical DNA strands are created, each with one old and one new strand

Mitosis

Process where replicated chromosomes are separated into two identical daughter cells

Genetic code

The complete set of genes in an organism's DNA

Aerobic cellular respiration

Chemical process in mitochondria producing energy (ATP) from food and oxygen

Biotic factors

Living parts of an ecosystem affecting carrying capacity

Abiotic factors

Non-living parts of an ecosystem influencing carrying capacity

Carrying capacity

Maximum number of individuals an environment can sustain

Biodiversity

Variety of life in a place, including genetic, species, and ecosystem diversity

Trophic level

Each level in a food chain or web indicating an organism's feeding level

Carbon cycle

Cycling of carbon among biosphere, atmosphere, hydrosphere, and geosphere

Ecosystem stability

Ability of ecosystems to maintain consistent organisms despite changes

Habitat fragmentation

Destruction of habitat leading to smaller, unconnected areas

Invasive species

Non-native species causing ecological or economic harm

Overharvesting

Unsustainable harvesting of plants or animals harming ecosystems

Pollution

Release of harmful substances damaging native ecosystems

Meiosis

Cell division producing haploid gametes for sexual reproduction

Fertilization

Fusion of sperm and egg forming a diploid zygote

Genetic variation

Differences in alleles due to crossing over, segregation, or mutations

Mendelian inheritance

Patterns of inheritance based on probability and genetic combinations

Homozygous

Having two of the same alleles for a trait (example RR or rr)

Heterozygous

Having two different alleles for a trait (example Rr)

Punnett Square

A diagram used to predict the possible genotypes of offspring in a genetic cross

Alleles

Different forms of a gene that occupy the same position on homologous chromosomes

Inheritance Patterns

Different ways in which genes and traits are passed down from parents to offspring

Dominant

An allele that is fully expressed in the phenotype of a heterozygote

Recessive

An allele that is masked in the phenotype of a heterozygote

Codominance

Both alleles in a heterozygote are expressed equally and separately

Sex-linked

Genes located on sex chromosomes, affecting traits differently in males and females

Polygenic

Inheritance pattern where multiple genes influence a single trait

Multiple alleles

More than two alternative versions of a gene for a specific trait

Environmental Factors

External elements that can influence genetic traits and their expression

Natural Selection

Process where organisms with advantageous traits survive and reproduce better

Biological Fitness

The ability of an organism to survive, reproduce, and pass on its genes

Convergent Evolution

Unrelated species develop similar traits due to similar environmental pressures

Divergent Evolution

Related species evolve different traits due to adapting to different environments

Endosymbiosis

Theory that mitochondria and chloroplasts were once free-living bacteria

Reproductive Isolation

Inability of species to interbreed successfully due to various barriers