SBI3U Genetic Processes - Unit Review

Cell Division - Mitosis, Asexual Reproduction

• Genetics is the study of heredity, while heredity refers to the transmission of traits from parents to offspring.
• A gene is a segment of DNA that carries information, while a locus is the location of a gene on a chromosome.
• Chromatin is the thread-like structure of DNA in the nucleus, which condenses into chromosomes during cell division.
• Sister chromatids are identical copies of a chromosome that are joined together.
• Mitosis is the process of cell division that results in two identical daughter cells, while cytokinesis is the division of the cytoplasm.
• Asexual reproduction involves the production of offspring genetically identical to the parent, while sexual reproduction involves the fusion of gametes to produce offspring with unique genetic combinations.

Meiosis & Sexual Reproduction

• Meiosis is the process of cell division that results in four haploid daughter cells, each with unique genetic combinations.
• The main events of meiosis include: synapsis, crossing over, and the separation of homologous chromosomes.
• Diploid cells have two sets of chromosomes, while haploid cells have one set.
• Spermatogenesis is the process of sperm production, while oogenesis is the process of egg production.
• Meiosis is distinct from mitosis in that it involves the shuffling of genetic material and the reduction of chromosome number.

Genetic Disorders, Karyotypes, etc.

• Non-disjunction disorders occur when chromosomes fail to separate properly during meiosis, resulting in abnormalities such as Down syndrome, Turner syndrome, and Klinefelter syndrome.
• Prenatal testing methods include amniocentesis and chorionic villus sampling, which can detect genetic abnormalities.
• A karyotype is a visual representation of an individual's chromosomes, which can be used to identify genetic abnormalities and sex chromosomes.
• Assisted reproductive technologies (ART) include in vitro fertilization (IVF) and artificial insemination, which can be used to help individuals with infertility or genetic disorders.
• Genetic mutations can cause genetic disorders such as cystic fibrosis, breast cancer, and phenylketonuria (PKU).

Patterns of Inheritance

• Mitochondrial DNA is passed on from mother to offspring through the egg cell.
• A gene is a segment of DNA that carries information, while an allele is a variant of a gene.
• Dominant and recessive alleles determine the expression of traits, with dominant alleles masking the effects of recessive alleles.
• Homozygous individuals have two identical alleles, while heterozygous individuals have two different alleles.
• Genotype refers to the genetic makeup of an individual, while phenotype refers to the physical expression of traits.
• Mendel's laws of inheritance include the law of segregation and the law of independent assortment, which describe how alleles are inherited.
• Punnett squares can be used to predict the probability of certain traits being expressed in offspring.

Structure of DNA & Mutations

• DNA is composed of nucleotides, which are linked together to form a double helix structure.
• Complementary base pairing occurs between adenine (A) and thymine (T), and between guanine (G) and cytosine (C).
• Mutations can occur in DNA, including point mutations, frameshift mutations, and chromosomal mutations.