Biology Year 10 Topic Test 1 PDF

**What are chromosomes / DNA** - Cell contains all of the organism's genetic instructions stored in the DNA - DNA molecule is tightly wound and packaged as a chromosome - 2 sets of 23 chromosome in every cell (46 total) 23 from each parent **Structure of DNA** - Double helix shape s...

**What are chromosomes / DNA** - Cell contains all of the organism's genetic instructions stored in the DNA - DNA molecule is tightly wound and packaged as a chromosome - 2 sets of 23 chromosome in every cell (46 total) 23 from each parent **Structure of DNA** - Double helix shape structure - Each side of ladder made of alternating deoxyribose sugar and Phosphate molecules - The rungs of ladder = 4 types of nitrogen bases -- Adenine, Guanine, Thymine, Cytosine (A T G C) - Base pair Rule: A-T together, G-C together - Attach at the sugars - Combination of a single base, a deoxyribose sugar, a phosphate = nucleotide (DNA = Nucleotide repeated)  **Chromosomes in Human cells** - Chromosomes located in the nucleus of cell - Karyotype -- photograph of chromosomes of one cell in homologous pairs -- can be use to identify disorderd/diseases - Homologous pairs = same length, bonding pattern, position of centromere - Chromosome \#23 not homologous in males (x,y) x larger than y - Chromosome \#1 - \#22 called autosomes make us humans/ carry most of our - Chromosome \#23 -- sex chromosome (male or female) gender specific genes - Diploid number - all chromosomes from parents (46) - Haploid number -- all chromosome from one parent (23) always half of diploid number - Condition Trisomy -- 3 copies of a particular chromosome instead of 2 - Alleles -- a version of a gene -- can carry disease or disorders associated with chromosomes e.g. \#2 Dyslexia, \#13 lung cancer - Genes -- regions of chromosome that codes for a protein or particular characteristic - appear as bands -- Called DNA coding - Before cell can divide, DNA inside must copy itself and go into 2 new cells - Mother cell divides into 2 daughter cells - DNA Polymerase links the half of the parent stand with the half of the new daughter stand. The original strands act as a template for the new daughter strand - 50% of strand parent and 50% daughter - Type of cell division that happens all over the body except for gametes (sex cells) - For growth, repair and replacement of cells - 2 identical DNA pieces are called sister chromatids Stages of Mitosis  **Cell Cycle** - S- synthesis phase -- DNA replicates so there are 2 copies of each chromosome - G2 -preparation for mitosis - M- Mitosis (**I -PMAT- C)** each chromosome copy moves to the opposite end of the cell in preparation for cytokinesis - G1 -growth phase cell is carrying out normal function Mitosis -- cell division that enables the cells to produce identical copies of themselves Meiosis - cell division that leads to the production of gametes **Sexual Reproduction** - Male gametes -- sperm, females gametes -- ovum - New organism is made when 2 gametes fuse together in the prosses of fertilization, cells that result from this -- **Zygote** REMINDER READ PAGE 51 **Meiosis** - Producing an organism: Prosses of Meiosis:  **Genetics**  **Punit Square -- Need to know prosses**  **Sex Linked Inheritance** - x chromosome can carry diseases, more common in men as they don't have another x chromosome to masked the other faulty x allele. - Haemophillia is a recessive X-linked disease - Women can have the recessive alle making them carriers or have the disease - Males will either have the disease or not **Complete all genetic problems in book** **Inheritance for Autosomal Traits -- Pedigree charts** - shows the occurrence and appearance of a particular genetic trait passed down in generations - **\ ** A diagram of a family tree Description automatically generated  **Explanation of Pedigree -- Use questions above to answer questions**  **HGP -- Human Genome Project** - 13 year to complete - Aim -- sequence the order of the four bases in the entire human genome - Sequencing allows researchers to identify important genes -- better understand diseases - Largest biological research project ever undertaken -- 1000's of staff around the globe - 20 different institutes from 6 countries **Ethics -- privacyand discrimination -- public all accessible risl of being denied a job or obtaining health insurance based on the genetic infor which risks of chronic disease** **Psychological impacts -- interpretation of genetic tests results can be hard. Seeing s cancer gene does not automatically mean they will develop cancer just that there is a risk information may be psychologically damaging for a person especially if the disease has no cure.**  **Genetic testing of Adults** - Presence of a particular allele will mean the person develops a disorder - If you have a lot of members of your family with something like breast cancer - Identifies the presence of specific alleles. - For some disorders the presence of a particular allele will mean the person will have an increased risk of developing the disorder or will develop the disorder, for some genetic testing can enable rapid treatment of genetic conditions to improve the person survival. Some may take this information and start preventative measures e.g. finding out you carry the gene for breast cancer and having your breasts surgically removed. - A preventative mastectomy reduced the risk of cancer by 90% - Gives them awareness and options to prevent future suffering **Huntington's Disease** **PGD**  A screenshot of a medical report Description automatically generated  Cons -- page 114 Pros - pages 115 **Gene Therapy** **and Cystic Fibrosis**  **Process has to be repeated every few months to treat CF** - **Gene cannot insert into wrong location or it will interfere with other genes -- non functioning protiens** **CRISPR -- Genetic Editing** **CRISPR** cuts out mutated DNA/alleles and implants a repaired/healthy/normal alleles back into Genome so cell division can occur and healthy cells spread through the body. - Gene Editing is permanent. Can treat CF -- used in embryo's and can correct a mutation Applications/ potential uses for CRISPR Technology - Treating disease - Improving yields and nitrous value in foods - Eradicate disease/ mutations in babies Ethical Considerations - Should it only be available to the wealthy - Should changes be made to embryo genome's that will be passed onto future generations -- removes embryo's right to consent and future generations GMO +-----------------------+-----------------------+-----------------------+ | Flavour saver | Bacteria is added to | Increases the shelf | | Tomatoes | DNA | life | | | | | | GM tomatoes | | - Stays firm | | | | | | | | - Reduces spoilage | | | | during transport | +=======================+=======================+=======================+ | Enviro Pig | Bacteria into Pig DNA | Allow it to produce | | | | enzymes that digests | | | | phosphate | | | | | | | | - Reduces | | | | environmental | | | | contamination | +-----------------------+-----------------------+-----------------------+ | GM Cotton | Bacteria into cotton | Cotton produces | | | DNA | spikey protein that | | | | kills caterpillars | | | | when they eat plant | +-----------------------+-----------------------+-----------------------+ | Alzheimer's Mice | Human gene inserted | - Produce plague in | | | into DNA | brain | | | | | | | | - Allow treatments | | | | to be tested on | | | | the animals | | | | before on humans | +-----------------------+-----------------------+-----------------------+ +-----------------------------------+-----------------------------------+ | Anti GM | Pro GM | +===================================+===================================+ | - reduce pests and weeds | - Growing GM crops near organic | | | farms (lose certification) | | - reduces plant disease | | | | - Some people are concerned | | - reduces management costa | that GM food could transfer | | | antibiotic resistance genes | | | to bacteria in our bodies, | | | making diseases harder to | | | treat with antibiotics | | | | | | - Some people are concerned | | | that inserting new genes into | | | plant cells, could let the | | | plant produce proteins that | | | are toxic, or cause an | | | allergic reaction | +-----------------------------------+-----------------------------------+