Brigidine College - Year 10 Natural Science - Biology Unit Term 2 - 2025

Transmission of Heritable Characteristics

Transmission of heritable characteristics from one generation to the next involves DNA and genes $(ACSSU184)$ .

Vocabulary

Eukaryotes: Organisms with cells containing a nucleus and other membrane-bound organelles.
Prokaryotes: Organisms with cells lacking a nucleus or other membrane-bound organelles.
Animal Cells: Eukaryotic cells with specific structures like centrioles.
Plant Cells: Eukaryotic cells with specific structures like chloroplasts and cell walls.
Organelles:
- Chloroplasts: Site of photosynthesis in plant cells.
- Nucleus: Contains the cell's genetic material (DNA).
- Mitochondria: Site of cellular respiration, producing energy for the cell.
- Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
- Endoplasmic Reticulum: Involved in protein and lipid synthesis.
- Lysosomes: Contains enzymes for breaking down waste materials and cellular debris.
- Ribosomes: Site of protein synthesis.
- Cytoplasm: The gel-like substance within the cell membrane, excluding the nucleus.
- Centrioles: Involved in cell division in animal cells.
- Vacuoles: Storage structures for water, nutrients, and waste products.
- Cell Walls: Rigid outer layer of plant cells, providing support and protection.
- Cell Membranes: Controls the movement of substances in and out of the cell.
Cell Division: Process by which cells multiply.
DNA: Deoxyribonucleic acid, the molecule that carries genetic information.
Double Helix: The structure of DNA, resembling a twisted ladder.
Nucleotides: The building blocks of DNA, consisting of a sugar, a phosphate group, and a nitrogenous base.
- Base Pairs:
  - Thymine (T) & Adenine (A): Complementary bases that pair together in DNA.
  - Cytosine (C) & Guanine (G): Complementary bases that pair together in DNA.
Genes: Segments of DNA that code for specific traits.
Chromosomes: Structures made of DNA and proteins that carry genes.
Karyotype: The number and appearance of chromosomes in the nucleus of a eukaryotic cell.
Chromatids: Two identical copies of a chromosome that are joined together.
Centromeres: The region of a chromosome where the two sister chromatids are attached.
Trait: A characteristic or feature of an organism.
Haploid: Having a single set of chromosomes (n).
Diploid: Having two sets of chromosomes (2n).
Mitosis: Cell division that results in two identical daughter cells.
- Prophase: Chromosomes condense and become visible.
- Metaphase: Chromosomes line up in the middle of the cell.
- Anaphase: Sister chromatids separate and move to opposite poles of the cell.
- Telophase: Chromosomes decondense and new nuclei form.
Meiosis: Cell division that results in four daughter cells, each with half the number of chromosomes as the parent cell.
Cytokinesis: The division of the cytoplasm to form two separate cells.
Centrioles: Involved in the formation of spindle fibers during cell division.
Spindle Fibers: Structures that separate chromosomes during cell division.
Gametes: Sex cells (sperm and ova) with a haploid number of chromosomes.
Sperm and Ova: Male and female gametes, respectively.
Fertilization: The fusion of sperm and ovum to form a zygote.
Zygote: The cell formed by the fusion of sperm and ovum.
Somatic Cells: Any biological cells forming the body of a multicellular organism other than gametes, germ cells, gametocytes or undifferentiated stem cells.
Autosomes: Non-sex chromosomes.
Sex Chromosomes: Chromosomes that determine sex (e.g., X and Y chromosomes).
Sugar-Phosphate Backbone: The structural framework of DNA, composed of alternating sugar and phosphate molecules.
DNA Replication: The process by which DNA copies itself.
Triplet Code: A sequence of three nucleotides that codes for a specific amino acid.
Amino Acids: The building blocks of proteins.
Mutation Types:
- Point Mutations: Changes in a single nucleotide base.
- Frameshift Mutations: Insertion or deletion of nucleotides, causing a shift in the reading frame.
Alleles: Different versions of a gene.
Inheritance: The transmission of traits from parents to offspring.
Dominant: An allele that masks the expression of another allele.
Recessive: An allele whose expression is masked by a dominant allele.
Genotype: The genetic makeup of an organism.
Phenotype: The observable characteristics of an organism.
Punnett Squares: A diagram used to predict the outcome of a genetic cross.
Codominance: Both alleles are expressed equally in the phenotype.
Incomplete Dominance: The phenotype is a blend of both alleles.
Purebred: An organism with homozygous alleles for a particular trait.
Hybrid: An organism with heterozygous alleles for a particular trait.
Heterozygous: Having two different alleles for a particular trait.
Homozygous: Having two identical alleles for a particular trait.
Monohybrid Cross: A cross between individuals that differ in a single trait.
Dihybrid Cross: A cross between individuals that differ in two traits.
Carrier: An individual who carries a recessive allele but does not express it in their phenotype.
Sex-linked (X-linked) Inheritance: Inheritance of genes located on the X chromosome.
Blood Types: Determined by the presence or absence of certain antigens on red blood cells.
Simple Pedigree: A diagram that shows the inheritance of a trait in a family.
X-linked Genes: Genes located on the X chromosome.
Variation: Differences in traits within a population.

Cell Structure

Describe differences between eukaryotes and prokaryotes
Draw and describe differences and similarities between animal and plant cells
Identify and label organelles on a diagram
Describe the function of the following organelles: nucleus, cell wall, cell membrane, cytoplasm, chloroplasts, mitochondria, ribosomes, endoplasmic reticulum, golgi body, vacuoles, lysosomes, centrioles

Cell Division and Differentiation

Define haploid and diploid
Explain similarities and difference between Mitosis and Meiosis
Accurately draw Stages of Mitosis (PMAT) and Meiosis (PMATPMAT)
Differentiate between cells, tissues, and organs

Chromosomes and DNA

Explain chromosomes, chromosome structure, genes and Inheritance.
Understand Chromosome numbers, shape and karyotype
Describe Fertilsation process: gametes, zygote
Explain how the biological sex of a baby is determined: chromosome 23 (XX or XY).
Understand chromosomal disorders eg. Down syndrome (Trisomy 21), Kleinfelter’s (XXY) Turner syndrome (X)
Describe the structure of DNA – double helix
Describe DNA replication: structure of the ‘building blocks’ (nucleotide)
Understand base molecules and the DNA code
Understand the triplet code and how they code for amino acids
Describe the role that DNA plays in inheritance
Explain how mutations occur and identify examples.
Investigate DNA and amino acid sequences to determine type of mutation

Genetics and Inheritance

Distinguish between genes and alleles
Define and compare the following terms: dominant and recessive
Distinguish between genotypes and phenotypes
Define and compare the following terms: homozygous and heterozygous
Draw monohybrid and dihybrid crosses
Predict the outcome of genetic crosses using Punnett squares (genotypes and phenotypes)
Define and explain sex-linked inheritance
Define and compare the following terms: codominance and incomplete dominance
Understand blood types (genotypes and phenotypes)
Explain how both genetic and environmental factors determine phenotypes
Complete a range of questions on the topic of Genetics and Inheritance

Communication and Skill

Communicate scientific meaning
Draw cell division diagrams
Interpret result tables and graphs
Draw and label scientific drawings
Analyse results
Write detailed conclusions
Carry out research activities
Completion of a range of questions including comprehension
Evaluate and write extended responses
Evaluate senarios and write justified conclusions
Interpret and compare unfamiliar graphs and results