Master the Fundamentals of Biology (Part 2 of 4) NEW

Explore how genes in DNA determine protein production through protein synthesis, detailing codons, amino acids, mRNA messaging, ribosomes, and the roles of noncoding regions, transcription, and RNA polymerase.

Explore the differences between dna and rna, noting dna is double-stranded while rna is single-stranded, their transport across the cell membrane, and the bases thymine versus uracil.

In transcription, RNA polymerase binds to a non-coding DNA region, unzips the strands, copies the gene into messenger RNA, and releases mRNA to the cytoplasm to join a ribosome.

During translation, ribosomes use mRNA codons to guide tRNA delivery of amino acids, whose anticodons pair with codons to assemble a protein in the cytoplasm.

Explore mitosis as the first type of cell division in asexual reproduction and diploid body cells, producing genetically identical offspring and enabling rapid growth, with mutations introducing variation.

Learn the steps of mitosis: DNA in the nucleus forms X-shaped chromosomes, they align at the center, membranes form around each set, cytoplasm divides, yielding two identical cells.

Explore meiosis, the cell division that produces haploid gametes—sperm and eggs—enabling fertilization and genetic variation. Note that cells from meiosis are not genetically identical, unlike those produced by mitosis.

Meiosis creates haploid gametes for sexual reproduction, which fuse during fertilization to form a zygote that then grows by mitosis into an embryo and human; offspring are genetically unique.

Meiosis executes two divisions, yielding four haploid gametes. Division one aligns homologous chromosomes and exchanges genetic material, while division two separates chromosome arms to produce genetically different gametes.

Explore the structure and function of flowers, focusing on the stamen and carpel. Learn how pollen lands on the stigma and forms a diploid zygote.

Explain pollination mechanisms by tracing pollen transfer from stamens to stigma, contrasting cross-pollination by insects or wind with self-pollination within the same plant.

Explore how pollen lands on stigma, grows a pollen tube through the style to the ovary via the micro pile, fertilisation forms a zygote that becomes an embryo and seed.

Explore seed germination in plants, detailing how water, oxygen, and the correct temperature trigger enzyme activity and energy release from seed reserves, leading to green leaves and photosynthesis.

Explore natural and artificial asexual reproduction in plants, illustrated by strawberry runners that form adventitious routes, producing genetically identical offspring; learn how cuttings and growth regulators boost artificial propagation.

Explore human reproduction through puberty and hormones, detailing primary and secondary sexual characteristics, and how testosterone and estrogen drive fertility, menstruation, ovulation, and sexual maturity.

Explore the female reproductive system, including the ovary, fallopian tube, endometrium, uterus, cervix, and vagina, and learn how estrogen and progesterone relate to ovum, implantation, embryo development, and pregnancy.

Explore the male reproductive system anatomy, including glands, vas deferens, erectile tissue, urethra, testes, and the scrotum, and how sperm are produced and deposited during ejaculation.

Explain how sperm deposited in the vagina reach the fallopian tube to fertilize the ovum, with enzymes penetrating the egg membrane, the zygote forming, and development into an embryo.

Learn about the four stages of the menstrual cycle, including the endometrium breakdown, its buildup, ovulation on day 14, and hormone-driven maintenance by FSH, estrogen, LH, and progesterone.

Trace how fertilization in the fallopian tube forms a zygote, implants in the uterus, and leads to embryo and fetus development with placenta-driven maternal-fetal exchange and amniotic fluid protection.

Explore genetic diagrams to understand inheritance, detailing how alleles, dominant and recessive traits, genotypes and phenotypes shape offspring using genetic diagrams and Punnett squares.

Learn to draw and interpret genetic diagrams with a punnett square. Determine offspring brown or blue eye phenotypes from heterozygous parents and identify Bb, BB, and bb genotypes.

Solve a Punnett square for a BB × bb cross in rats to show all offspring are heterozygous Bb with brown eyes, yielding 100% brown phenotype and 0% blue.

Present classic genetic diagrams for two heterozygous parents, showing sickle cell inheritance with dominant and recessive alleles, gametes, phenotypes, and offspring genotypes in four outcomes.

Explore codominance through genetic diagrams and see how both alleles express traits. Blood groups A, B, and AB demonstrate codominant inheritance with a 25% A, 25% B, and 50% AB.

Explore family pedigrees and how cystic fibrosis follows a recessive inheritance, showing that two heterozygous parents can have a 25% chance of an affected child.

Discover how phenotype equals genotype plus environment, and how varying environments create phenotypic variation even with the same genes, illustrated by plants grown with or without light.

Examine genetic variation from genotype via random mating and fertilization, and how environment contributes to variation in traits like height, intelligence, and plant growth, while eye color remains unaffected.

Explain how variation within and between populations, driven by genotype and environment, leads to evolution over vast timescales, with humans and primates originating from a single ancestor.

Natural selection drives evolution by favoring individuals with advantageous variations that improve survival and reproduction amid competition for resources, passing those genes to future generations.

Explore how mutations alter the DNA base sequence of a gene, creating new phenotypes and genetic variation through inherited changes, occasionally harmful or useful, and affecting protein function.

Explore how rapid bacterial reproduction and random mutations drive antibiotic resistance through natural selection, and learn why finishing prescribed antibiotic courses helps prevent resistant strains.