11.4 Sexual reproduction: Sexual reproduction involves the development and fusion of haploid gametes.
Nature of science: Assessing risks and benefits associated with scientific research—the risks to human male fertility were not adequately assessed before steroids related to progesterone and estrogen were released into the environment as a result of the use of the female contraceptive pill.
∑ - Spermatogenesis and oogenesis both involve mitosis, cell growth, two divisions of meiosis and differentiation.
Similarities between Spermatogenesis and Oogenesis (use the above information to fill in the table below)
∑ - Processes in spermatogenesis and oogenesis result in different numbers of gametes with different amounts of cytoplasm. (Differences in the outcome of spermatogenesis and oogenesis
|Occurs in males (testis)||Occurs in females (ovaries)|
|Four male gametes (spermatids) are produced through meiosis for every germ cell.||One female gamete (ovum) and 3 polar body cells for every germ cell are produced through meiosis.|
|Each sperm cell is small and contains little cytoplasm||The large egg cell contains large amounts of cytoplasm and the 3 polar bodies produced degenerate|
|Millions of sperm produced every day from puberty until a man dies.||One secondary oocyte is ovulated every month during the menstrual cycle until a woman reaches menopause.|
|Spermatozoa are released during ejaculation. ||Secondary oocytes are released during ovulation.|
Skill: Annotation of diagrams of seminiferous tubule and ovary to show the stages of gametogenesis.
∑ - Fertilization involves the acrosome reaction, fusion of the plasma membrane of the egg and sperm and the cortical reaction.
Skill: Annotation of diagrams of mature sperm and egg to indicate functions.
∑ - Fertilization in animals can be internal or external.
∑ - Fertilization involves mechanisms that prevent polyspermy.
∑ - Implantation of the blastocyst in the endometrium is essential for the continuation of pregnancy.
Video: - https://www.youtube.com/watch?v=3u251OXfsRU
∑ - HCG stimulates the ovary to secrete progesterone during early pregnancy
∑ - The placenta facilitates the exchange of materials between the mother and fetus.
Materials are exchanged between the maternal and the fetal blood in the placenta.
Note: maternal and fetal blood is never mixed together.
|Materials passed from fetus to mother||Materials passed from mother to fetus|
|Water||Nutrients (i.e. glucose and amino acids)|
|Hormones (i.e. HCG)||Vitamins and minerals|
∑ - Estrogen and progesterone are secreted by the placenta once it has formed.
***Do data based questions on page 507 and 508***
∑ - Birth is mediated by positive feedback involving estrogen and oxytocin.
***Do the data analysis questions on page 508 and 509***
β -Application: The average 38-week pregnancy in humans can be positioned on a graph showing the correlation between animal size and the development of the young at birth for other mammals.
***Do the data analysis on page 510***
β -Application: Disputes over the responsibility for frozen human embryos.
Topic 11: Animal physiology (16 hours)
11.1 Antibody production and vaccination: Immunity is based on recognition of self and destruction of foreign material.
∑ - Every organism has unique molecules on the surface of its cells.
Cell surface glycoproteins on the HIV virus above
β - Application: Antigens on the surface of red blood cells stimulate antibody production in a person with a different blood group.
∑ - Pathogens can be species-specific although others can cross species barriers.
Video on Zoonosis: https://www.youtube.com/watch?v=PSQPikvU6pc
∑ - B lymphocytes are activated by T lymphocytes in mammals.
∑ - Activated B cells multiply to form clones of plasma cells and memory cells.
∑ - Plasma cells secrete antibodies.
∑ - Antibodies aid the destruction of pathogens.
Antibodies aid in the destruction of pathogens in a variety of ways
∑ - Immunity depends upon the persistence of memory cells.
∑ - Vaccines contain antigens that trigger immunity but do not cause the disease.
Herd Immunity - http://www.cbc.ca/news/health/measles-vaccinations-of-toddlers-at-89-below-herd-immunity-level-1.3161617
***Do Data Based questions on page 473**
β - Application: Smallpox was the first infectious disease of humans to have been eradicated by vaccination. Human vaccines are often produced using the immune responses of other animals.
Good video on smallpox https://www.youtube.com/watch?v=yqUFy-t4MlQ
Eradication of smallpox in South-East Asia
Nature of science: Consider ethical implications of research—Jenner tested his vaccine for smallpox on a child.
Jenner’s Story http://www.sciencechannel.com/tv-shows/greatest-discoveries/videos/100-greatest-discoveries-the-beginning-of-vaccination/
Ethics in medicine: http://study.com/academy/lesson/ethical-issues-in-medicine-psychology.html
β - Skill: Use databases to analyse epidemiological data related to vaccination programmes
Epidemiological Studies on Vaccinations
Vaccines and Autism http://www.ageofautism.com/2011/05/vaccines-and-autism-what-do-epidemiological-studies-really-tell-us.html
[Polio notifications, Ireland 1948-2010 (as of 14/10/2010)]
∑ - Histamines cause allergic symptoms.
∑ - Fusion of a tumour cell with an antibody-producing plasma cell creates a hybridoma cell.
∑ - Monoclonal antibodies are produced by hybridoma cells.
Video on Monoclonal Antibodies https://www.youtube.com/watch?v=kcxQyIfca4I
β - Application: Monoclonal antibodies to HCG are used in pregnancy test kits.
Use in diagnosis of pregnancy
Use in treatment of rabies
**Other examples are treatment of cancer cells and detection of HIV**
11.3 The kidney and osmoregulation: All animals excrete nitrogenous waste products and some animals also balance water and solute concentrations.
Nature of science: Curiosity about particular phenomena—investigations were carried out to determine how desert animals prevent water loss in their wastes.
∑ - Animals are either osmoregulators or osmoconformers.
***Data Based Questions p.486***
∑ - The Malpighian tubule system in insects and the kidney carry out osmoregulation and removal of nitrogenous wastes.
∑ - The composition of blood in the renal artery is different from that in the renal vein.
***Data Based p.488***
β - Skill: Drawing and labelling a diagram of the human kidney.
Animation of how the kidney works: https://www.youtube.com/watch?v=hiNEShg6JTI&nohtml5=False
∑ - The ultrastructure of the glomerulus and Bowman’s capsule facilitate ultrafiltration.
|Molecule (mg 100 ml-1)||Blood Plasma||Glomerular Filtrate||Urine|
** Please note the concentrations can vary because of diet and salt and water intake**
∑ - The proximal convoluted tubule selectively reabsorbs useful substances by active transport.
Selective Reabsorption: https://www.youtube.com/watch?v=2_AvOs9fAlY&nohtml5=False
∑ - The loop of Henle maintains hypertonic conditions in the medulla.
Countercurrent flow: https://www.youtube.com/watch?v=_sw6otQOkMQ&nohtml5=False
∑ - ADH controls reabsorption of water in the collecting duct.
∑ - The length of the loop of Henle is positively correlated with the need for water conservation in animals.
The longer the loop of henle, the more water will be reabsorbed
Therefore, animals that live in dry habitats such as the desert have a long loop of Henle
This means the medulla of the kidney is also thicker
Animals that live in the desert (loop of Henle in Kangaroo rat 1:10-1:30)
∑ - The type of nitrogenous waste in animals is correlated with evolutionary history and habitat.
Crash Course on Excretory System: https://www.youtube.com/watch?v=WtrYotjYvtU&nohtml5=False
Applications and skills:
β - Application: Consequences of dehydration and overhydration.
β - Application: Treatment of kidney failure by hemodialysis or kidney transplant.
β - Application: Blood cells, glucose, proteins and drugs are detected in urinary tests.
Urine tests are used to detect abnormalities and possible diseases
β - Application: The removal of kidney stones by ultrasound treatment.
Kidney stones explanation: https://www.youtube.com/watch?v=kd1OgaoHkNk&nohtml5=False
Ultrasound surgery of Kidney Stones: https://www.youtube.com/watch?v=fR_CjlVXhzw&nohtml5=False
Skill: Annotation of diagrams of the nephron including the glomerulus, Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule; the relationship between the nephron and the collecting duct should be included.
11.2 Movement: The roles of the musculoskeletal system are movement, support and protection.
∑ - Bones and exoskeletons provide anchorage for muscles and act as levers.
∑ - Synovial joints allow certain movements but not others.
|Hip Joint (differences)||Similarities||Knee joint (differences)|
|Ball and socket joint||Synovial joints separated by a fluid-filled cavity||Hinge joint|
|Free movement in all three planes||Fluid is called synovial fluid that lubricates the joint.||Allows movement in one plane (although there can be slight side to side movement)|
|Greater range of motion than the knee joint (flexion, extension, adduction, abduction and rotation). Muscles involved are the quads, hamstrings, gluteus maximus and many other smaller muscles||Ends of bones covered in cartilage, a smooth connective tissue which absorbs shocks more easily.||Motions are flexion (contraction of hamstring muscle) and extension (contraction of quadriceps muscles)|
β -Skill: Annotation of a diagram of the human elbow: include cartilage, synovial fluid, joint capsule, named bones and named antagonistic muscles.
|cartilage - stiff yet flexible connective tissue found in many areas in the bodies such as the joints between bones, nose and ear||cartilage reduces friction in the joint, provides high tensile strength and support, and absorbs compression|
|synovial fluid – thick, viscous fluid found in the cavity of the synovial joints||synovial fluid reduces friction by providing lubrication between the cartilage and other tissues in joints during movement supplies oxygen and nutrients to and removes carbon dioxide and wastes from the cartilage cells|
|joint capsule – two-layered sac surrounding the joint made from fibrous tissue||The joint capsule seals the joint space and provides stability to the joint by limiting movements|
|radius – smaller forearm bone that extends from the lateral side of the elbow to the thumb part of the wrist||Lever attached to the biceps. When the biceps contract, the radius provides a solid structure for lifting|
|ulna – longer forearm bone on the medial side||Lever connected to the triceps. When the triceps contract, the ulna provides support as a lever as the arm straightens out|
biceps – muscle connected to the radius
contracts and causes flexion (arm bending)
|triceps – muscle attached ulna||contracts and causes extension (arm straightening)|
***Data Based questions on page 477***
∑ - Movement of the body requires muscles to work in antagonistic pairs.
β - Application: Antagonistic pairs of muscles in an insect leg.
Grasshopper jumping https://www.youtube.com/watch?v=cevL1RWcmqQ&list=PL0LFUbJiCoV67pVzNYsDnRE3roiMeCX3c&index=5
Interesting video http://www.smithsonianmag.com/science-nature/this-insect-has-the-only-mechanical-gears-ever-found-in-nature-6480908/?no-ist
∑ - Skeletal muscle fibres are multinucleate and contain specialized endoplasmic reticulum.
∑ - Muscle fibres contain many myofibrils.
∑ - Each myofibril is made up of contractile sarcomeres.
Myofibrils – rod-shaped parallel bodies consisting of actin and myosin filaments
Sarcolemma – plasma membrane of the muscle cell.
Mitochondria – large numbers; found dispersed around individual myofibrils.
β - Skill: Drawing labelled diagrams of the structure of a sarcomere: include Z lines, actin filaments, myosin filaments with heads, and the resultant light and dark bands.
***Do data-based questions on page 481***
∑ - The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments. Use animations to visualize contraction.
Good videos on cross-bridge formation and muscle contraction:
∑ - Calcium ions and the proteins tropomyosin and troponin control muscle contractions.
∑ - ATP hydrolysis and cross bridge formation are necessary for the filaments to slide
β - Skill: Analysis of electron micrographs to find the state of contraction of muscle fibres. Measurement of the length of sarcomeres will require calibration of the eyepiece scale of the microscope.
Muscle Fiber (contracted and relaxed)
β - Skill: Use of grip strength data loggers to assess muscle fatigue
Nature of science: Developments in scientific research follow improvements in apparatus—fluorescent calcium ions have been used to study the cyclic interactions in muscle contraction.
**Read through article and make notes**
Crash Course on Muscles: https://www.youtube.com/watch?v=jqy0i1KXUO4
IB Biology - Curriculum Notes