SCIENCE - SEMESTER ONE

• Define Genetics

  is the study of Genes
• Define Nucleotides

  is the basic building blocks of nucleic acid (RNA and DNA), which consists of phosphate, pentose sugar, and one of four nitrogenous bases.
• Define DNA

  stands for deoxyribonucleic acid, it is the molecule that carries the genetic information found in the cell of a living organism. It is unique to every individual and consists of two strands of nucleotides arranged in a ladder-like structure that coils around each other to form the double helix
• Define Chromosome

  is tightly wound DNA that wraps around proteins called histones.
• Define Genes

  is the unit of inheritance and a section of DNA that codes for protein synthesis.
• Define Centromeres

  joins together two identical chromatids
• Define Sister Chromatids

  two identical copies of chromatids
• Define Telomere

  the protective molecular caps of repeating DNA that is located at the ends of chromosomes.
• Define mRNA (messenger RNA)

  is a type of RNA that carries the genetic information from DNA to the ribosomes, which serves as a template of protein synthesis
• Describe the relationship between chromosomes, genes, DNA, and base pairs

  Chromosomes are long thread-like structures made up of DNA and proteins that may contain genes. Genes are specific sequences of DNA and codes for proteins.
• Define Transcription

  is the first stage of protein synthesis where the base sequence of DNA is copied into mRNA
• Define Translation

  is the second stage of protein synthesis where a sequence of mRNA is translated into a sequence of amino acids
• Define Base Triplets

  three grouped nucleotides in DNA that code for amino acid
• Define Codons

  three grouped nucleotides in mRNA that code for amino acid
• Define Proteins

  large molecules made up of amino acids and play an important role of the structure and function of a living organism.
• What is the purpose of DNA?

  making proteins
• State what RNA stands for

  ribonucleic acid
• State the structure and functions of DNA

  Structure: double stranded (double helix), has deoxyribose sugar, Bases: Adenine - Thymine and Cytosine - Guanine

  Function: stores and transfers genetic information, provides a template for protein synthesis
• State the structure and functions of RNA

  Structure: single stranded, has ribose sugar, Bases: Adenine - Uracil and Cytosine - Guanine

  Function: directly codes for amino acids and serves as a messenger of DNA and ribosome to make proteins
• Define Sexual Reproduction

  when gametes from the female and the male unit to produce and offspring genetically different from both the parents.
• Male gonads (testicle) produces sperm while female gonads (ovary) produces egg cells. Both of these gametes are haploid cells.
• Define Somatic cells


  the body cells of an organism
• Define Gametes


  the sex cells that combine to produce new offspring
• Define Diploid


  a cell containing two sets of chromosomes
• Define Haploid


  a cell containing only one set of chromosomes
• Define Zygote


  a fertilised egg produced by the fusion of male and female gametes
• Define Embryo


  the early stage of a living organism, a zygote eventually becoming an embryo
• Define Autosomes 


  1-22 pairs of chromosomes are known as autosomes which are non-sex chromosomes.
• Define Sex Chromosomes


  the 23rd pair of chromosomes that contains the genes determining the sex of the individual
• Define Karyotype


  an individuals complete set of chromosomes
• Homologous Chromosomes are matching chromosomes while Non-Homologous Chromosomes are chromosomes that do not match, not containing similar information
• What is the purpose of Mitosis

  cell division for growth, repair, and asexual reproduction
• What is the purpose for Meiosis

  specialised cell division for sexual reproduction
• Mitosis - is the process of nuclear division that forms two daughters cells with identical sets of chromosomes. (or number of diploid chromosomes)
• All somatic (non-reproductive) cells are formed by mitosis.
• Each cell of the body only produces two daughter cells
• Daughters cells contains the number of chromosomes as the original cell (diploid), in this way, every cell obtains a complete set of genetic information.
• Mitosis is located in the body, replaces old cells, ends with two daughter cells and is a diploid (2n).
• Meiosis is located at the gonads, produces gametes, ends with four daughter cells and is haploid (n)
• Meiosis - the process where the cell divides twice, forming four cells that contains half the genetic information (2n->n). It forms sperm and egg which is the sex cells or gametes.