Biology Sem 1 Year 12 Flashcards

Question

21. Define endotherm and ectotherm and recall an example of each type of animal.

Answer 1

An ectotherm (reptile/amphibian) relies primarily on its external environment to regulate the temperature of its body. Cold blooded. Have fluctuating body temperatures Endotherms (birds, humans, mammals) are able to regulate their body temperatures by producing heat within the body. Have stable body core temp.

Answer 2

Endotherms use internally generated heat to maintain body temperature. Use metabolic heat Behavioural, structural and physiological adaptations Numerous mechanisms and/or organs may be activated to warm up or cool down the body

Answer 3

-Conduction -heat moves to a cooler area via touch -sitting on cold metal bench and bench gains heat Convection: -movement of heat away from source via airflow -windy days are cooler than still days Radiation: -natural slow movement of heat away from a source -body naturally cools down by releasing heat in a cooler room.

Answer 4

Pathogen: Bacteria Cellular Features: prokaryotic (no cell organelles and single celled) -Fast reproduction through binary fission -destroying cells and tissues and/or producing harmful toxins Examples: Gastro, whooping cough Treatment: Antibiotics Pathogen: Fungi/ Yeast Cellular Features: single celled but eukaryotic spreads via spores contains cell walls Examples: Ringworm Treatment: Fungicides to treat fungal infections Pathogen: Protozoa Cellular Features: -has multiple life stages in different hosts -found in warm waterways -single celled -eukaryotic Examples fOWLERIA (brain eating ameoba) Malaria Treatment: hard to treat, extremely fatal,many different drugs have been tried Pathogen: Parasites (Multicellular, endoparasites) Cellular Features Internal infection Produces toxins to destroy cell and tissues Examples Flatworms, tapeworms, nematodes (hookworms, roundworms) Treatment: Passing worms naturalls, antiworming tables Pathogen: Parasites (Multicellular, ectoparasites) Cellular Features Attach on outside of host (ecto) Produce toxins Examples Fleas, ticks, mites Treatment: Lice shampoo, removal of parasite Pathogen: Virus Non Cellular Features -can only replicate inside a living host -infect all cellular organism -small Examples -covid -common flu -cold sores Treatment: Antivirals to stop virus from hijacking the cells genetic material Pathogen: Prions Non Cellular Features Misfolded proteins Affects the nervous system -Transmissible through eating another infected thing Examples Mad Cow Disease Treatment: no cure, universally fatal

Answer 5

any condition that adversely affects the normal functioning of any part of a living thing -this would include serious injury which inst a disease

Answer 6

Infectious: a disease caused by an organism or infective agent (pathogen) Non-infectious: a disease that is not caused by a pathogen, and, with the exception of inherited diseases, cannot be passed from one person to another

Answer 7

A disease causing agent or organism Can be cellular (considered to be living and made of cells) or non cellular Pathogens can be intracellular (inside of cell )or extracellular (outside of cell)

Answer 8

-they can reproduce rapidly in a nutrient rich environment -280 billion bacteria in 8 hours Pathogens may rapidly evolve and avoid the host immune response. Destroying cells and tissues with enzymes. * Producing toxins which are harmful to the host. * Causing the initiation of a debilitating immune system response.

Answer 9

A poisonous substance produced within living organisms Toxins are often proteins which interact and interfere with cells. Tetanus is caused by deadly toxins of bacteria

Answer 10

Antibiotics: anti-pathogenic substances produced by other microorganisms (e.g. fungi and bacteria). commonly used to fight bacterial infections * Antiseptics and disinfectants. * Antivirals, fungicides.

Answer 11

Disease transmission is not constant and will vary depending on type of disease, the population and the time

Answer 12

Endemic diseases – a disease that occurs at a relatively constant rate in the population Epidemic diseases – a disease that is uncommon, occurs when there is a spike in cases in the population above what is considered to be normal

Answer 13

Infectivity – How easily the pathogen can jump from host to host Virulence – the capacity of the pathogen to cause severe disease in the host How long the pathogen can persist in an asymptomatic host Pathogens want to spread to as many hosts as possible

Answer 14

Available infrastructure * Climate * Density of the population * Proportion of the population immune to infection * Movement of individuals in the population Amount of travel Planes make disease easy to spread Were there people wearing masks to reduce droplets?

Answer 15

- Pandemic, global outbreak of a disease Epidemic- widespread occurrence of an infectious disease in a community or in a restricted geographic area at a particular time An epidemic can develop into a pandemic, but not vice versa

Answer 16

Prevention: Hand Washing PPE Hygiene Disinfection Isolation Quarantine Control Carriers -kill infected herds -eliminate vectors (eg mosquitos) Vaccinate

Answer 17

Antibiotics work against bacteria – they kill bacteria or prevent their growth Antiviral drugs are specifically used to treat viral infections Often only effective only when the virus is located within a cell and is undergoing replication Antibiotics vs. Antivirals

Answer 18

Injection of deactivated pathogen (attenuated or killed), or toxoid (deactivated form of toxin) Injection still contains the antigen which provokes immune response, but does not cause the infection Promotes primary immune response, production of memory cells leads to acquired immunity and future protection Multiple injections (boosters) may be required over short term or long term to increase memory cell number.

Answer 19

If a large enough proportion of the population is immune to a disease, there are too few susceptible individuals to sustain disease spread Herd immunity is essential for the protection of those who cannot be vaccinated, or those with a suppressed immune system

Answer 20

Transmission by direct contact: Transmitted from one host to another when the skin of the two hosts come into contact Reproduction of the pathogen causes lesions containing millions of copies of the pathogen. These lesions are itchy, and scratching allows the spread of the pathogen Example: ;Chickenpox * Impetigo * Cold sores Bodily fluids: liquids that come from inside the body, including sweat, tears, vomit, nasal secretions, blood, saliva and urine Pathogens that are transmitted in this way need to be able to survive outside of the body for substantial periods of time. * Glandular fever * HIV * HPV Sexual contact, pregnancy, needle use, blood transfusions Food Borne transmission Pathogen enters the body via the gastrointestinal tract via food. Pathogen may spread to the food via faeces from an infected person, or meats may be infected by bacteria from the animal’s intestinal tract. Food poisoning – Salmonella, E. coli etc. Waterborne Transmissions Pathogen is spread via bodies of water. In many developing countries, sewage is can enter the waterways, which can lead to faecal-oral transmission of diseases Hepatitis A Airborne transmission Pathogen is spread via the air. Coughing or sneezing can release millions of microbes into the air in droplets of mucus or saliva. Some diseases promote this by causing excess nasal secretions. -common cold Transmission by vectors a living organism that transmits pathogens from one host to another, for example, mosquitoes enable a pathogen to penetrate the outer defences of the host in a way they cannot unassisted Malaria

Answer 21

The innate response (non specific) 1st and 2nd line of defence * Barriers to keep pathogens out; cells and molecules to indiscriminately destroy pathogens that get in. * A rapid response. Has no memory of the infection and therefore has no faster clearance on re-infection. The adapted/acquired response (specific) 3rd line of defence faster clearance rate on re-infection. Offers superior protection. can take up to 2 weeks to work

Answer 22

Animals: physical barriers Epithelial cells - Skin - Lining of the respiratory, gastrointestinal and urogenital tracts * Adaptations - Mucus-secreting membranes (mucus traps pathogens) - Membranes lines with cilia (attempt to sweep pathogen out) Plants: physical barriers Cell wall in plant cells * Bark in trees * Ability to close stomata * Positioning of leaves (so water does not collect on the surface and attract pathogens) Animal Chemical Barriers * Lysozyme enzymes and fatty acids – tears, sweat, saliva * Low pH – stomach, vagina ( areas that are prone to pathogens have low ph in an attempt to kill the pathogens) * Surfactants - lungs Plants Chemical Barriers Chemicals that inhibit the growth and development of pathogens - May be released into the environment - May remain in the plant * Defensins – small stable peptides that can inhibit development of fungi, bacteria, viruses and insects -caffeine, produced by plants is toxic to bugs and insects Animals- Microbial barriers Normal flora - Skin - In mouth, nose, throat, lower gastrointestinal tract, urogenital tract * Prevents growth and colonisation of other bacteria Bacteria lives a harmonious relationship with human , they can help to break down cellulose

Answer 23

Molecules Complement proteins: -system of over 20 proteins produced by liver and circulating in blood -Bind cellular pathogens and target them for destruction - Release chemical signals to attract phagocytes - Puncture bacterial cell walls and cause lysis - Help stimulate inflammation Cytokines: Small signalling molecules that coordinate much of the immune response Peptides, proteins or glycoproteins Released in response to cell damage or the presence of pathogens Can kill body cells 2 kinds of cytokines: interferons and chemokines Inteferons: -signals neighbouring uninfected cells to destroy RNA and reduce protein synthesis because they are factories for creating more virus if cell was to be infected in the future -signals neighbouring infected cells to undergo apoptosis (programmed cell death, cell implodes without affecting other cell/ tissue ) -activates immune cells Chemokines -attract leukocytes (white blood cell and immune cells) to site of infection and inflammation

Answer 24

1. Complement Proteins 2.Cytokines 3.Interferon 4.Chemokines 5. Nonspecific phagocytes

Answer 25

-cleans up dead bacteria and viruses -include macrophages, neutrophils, b cells and dendritic cells -in charge of eliminating micro organisms and showing them to the rest of the immune system.

Answer 26

redness, swelling, heat, pain and pus (largely composed of dead white blood cells – neutrophils). Response to cut through skin or presence of pathogen (infection). A mechanism of ensuring our ‘troops’ get to the location of the fight. Inflammation occurs because there are lots of immune cells at the sight, which also means the area can feel warmer

Answer 27

Blood platelets adhere to surface of any cut blood vessels to reduce blood loss and prevent bacteria spreading

Answer 28

An increase in the bodies set point temperature in response to infection (feel cold/chills even though body temp. is raised) In an attempt to kill pathogens that cannot withstand that temperature This can be dangerous because it effects bodies thermoregulation and enzymes must be at a set temp. May be triggered by molecules from the pathogens or cytokines released by macrophages. Thought to reduce the growth of bacteria and increase the effectiveness of the immune system

Answer 29

Neutrophils: Phagocytes Circulate in bloodstream First to arrive at infection sites Release compounds that disrupt bacterial and fungal membranes Release cytokines Macrophages: Phagocytes Found in tissues Eliminate microbes and cell debris Dendritic Cells: Phagocytes Found in tissues Engulf pathogens and present them to other cells Have many grooves, increasing surface area Constantly patrolling the bloodstream Natural Killer Cells: Recognise virus-infected and cancerous cells Circulate in the blood Trigger apoptosis in affected cells Release cytokines to attract and activate cells of the adaptive immune system Eosinophils: Secrete powerful enzymes capable of making holes in multicellular pathogens (such as flukes and parasitic worms) Basophils: circulate in the blood and secrete histamines when damaged

Answer 30

unique molecules found in all cells that can be recognised by our immune system Self Antigens: -found in bodies own cells and recognised as being a part of our own immune system Non Self antigens (mostly from pathogens) -recognised as not belonging (not a self antigen) so many induce an immune response In autoimmune diseases, the body attacks own antigens and organs

Answer 31

-how cells tell friends from foes -determined by the genotype of an individual, inque for each person MHC 1 markers -on all cells -shows the immune system what is inside each cell MHC 2 markers -on antigen presenting cells (not all cells) -antigen presenting cells include macrophages, dendretic cells and B lymphocytes to -shows that they have englufed pathogen -Presenting engulfed pathogens is the hallmark of the third line of defence

Answer 32

Humoral Immunity-Body fluid (blood etc, not in cells yet) -B lymphocytes and antibodies -(T helper cells (Th) and cytokines also involved) Fight occurs in the bodies ‘humours’ (body fluids Cell-Mediated Immunity: T lymphocytes T helper cells (Th), antigen presenting cells and cytokines also involved) Fights against intracellular pathogens

Answer 33

Body Fluid Draining Collects interstitial fluid (Fluid found in the spaces around cells. It comes from substances that leak out of blood capillaries )and filters it back into the blood system. Includes blind ending capillaries which collect into vessels and on to lymph nodes. Transports a range of white blood cells and is the site of much immune response Checks body fluid for anything foreign -Drainage Systems, constantly checking for pathogens -Anything leaking out of bloodstream is checked because lymphatic system is intertwined with vessels and arteries It includes: -lymph -lymph vessels -lymph nodes -spleen -thymus -Bone Marrow - produces red blood cell

Answer 34

Lymphocytes= immune cells made in the bone marrow 1. Cytotoxic T cells (CD8) -kill virus infected and damaged cells 2. hELPER t CELLS (CD4) -help cytotoxic t cells and b cells in their immune function (double checking) 3. B cells -produce antibodies Each lymphocyte has a different receptor for a particular antigen There is a diverse range of lymphocyte receptors One of these is the right shape to bind to the right antigen It is important that the antigen finds the right lymphocyte to bind with so that it can be replicated Clonal Population of lymphocytes- some of these will become effector cells and others memory cells All lymphocytes do this

Answer 35

Involves B lymphocytes which produce specific antibodies (glycoprotein molecules) against foreign antigens These antibodies are bound to the plasma membrane surface: * Act as receptors for binding an antigen * Stimulate further antibody production Also known as immunoglobulins (Ig) Bind to specific antigen molecules Y-shaped molecule that consists of: * Two identical long heavy chains * Two identical short light chains Antibodies have two distinct regions: * Constant region (can have one of 5 forms) * Variable region (can have infinite forms) The variable region allows different antigens to bind The constant region recruits other members of the immune system Antibody function Antibodies bind to antigens, forming an antigen- antibody complex. Leads to: * Neutralisation of bacterial toxins * Prevents pathogens binding to body cells * Agglutination – clumps the antigens together * Makes antigen more susceptible to the action of phagocytes * Activates complement proteins and cytotoxic T cells B lymphocytes are produced, and mature in, bone marrow .

Answer 36

You have billions of different types of B cells in your body, each with surface antibodies for different antigens. The type of antibody created depends on a semi-random genetic lottery. You have B cells with antibodies for antigens your body hasn’t met yet, or that doesn’t even exist yet. Any B cell with an antibody that recognises a self antigen is normally destroyed. This creates “tolerance of self”.

Answer 37

* Pathogens and antigens * T lymphocytes (T cells) – Cytotoxic T cells – Helper T cells * Antigen presenting cells Helper T cells and cytotoxic T cells. Produced in the bone marrow, migrate and mature in the thymus Have specific T cell receptors (TCR) on their membrane. T cells can’t recognise antigens on their own, it must be presented to them by Antigen Presenting Cells (APC) in order to become activated T helper cell will recognise specific complementary antigens on the MHC II markers of an APC. Once activated, Th cell will undergo clonal expansion (multiply) and produce effector and memory Th cells. Effector Th cells release cytokines to excite: Cytotoxic T cells. Activated B cells.

Answer 38

Memory T Cells (both helper and cytotoxic) generally remain for life and respond when they recognise the specific foreign antigen presented on MHC markers. Therefore the response to secondary infection is faster and larger.

Answer 39

Immunity May be innate, acquired or herd. Can be acquired naturally, meaning no ‘technological’ intervention, or artificially, through assisted measures. Can be acquired passively, through input of antibodies from another organism, or actively, through the bodies own immune response. Active Natural Immunity: Through the bodies own immune response to foreign antigens, B cells and T cells. Creates memory cells and long- term immunity. Passive Natural : Receiving already made antibodies. Does not lead to memory cell creation or long-term immunity. Protects foetus/child whilst their own immune system builds: – Foetus receives antibodies from mother across the placenta in the womb. – Child receives antibodies in breast milk.

Answer 40

Immunity May be innate, acquired or herd. Can be acquired naturally, meaning no ‘technological’ intervention, or artificially, through assisted measures. Can be acquired passively, through input of antibodies from another organism, or actively, through the bodies own immune response. Active Natural Immunity: Through the bodies own immune response to foreign antigens, B cells and T cells. Creates memory cells and long- term immunity. Passive Natural : Receiving already made antibodies. Does not lead to memory cell creation or long-term immunity. Protects foetus/child whilst their own immune system builds: – Foetus receives antibodies from mother across the placenta in the womb. – Child receives antibodies in breast milk.

Answer 41

Immunity May be innate, acquired or herd. Can be acquired naturally, meaning no ‘technological’ intervention, or artificially, through assisted measures. Can be acquired passively, through input of antibodies from another organism, or actively, through the bodies own immune response. Active Natural Immunity: Through the bodies own immune response to foreign antigens, B cells and T cells. Creates memory cells and long- term immunity. Passive Natural : Receiving already made antibodies. Does not lead to memory cell creation or long-term immunity. Protects foetus/child whilst their own immune system builds: – Foetus receives antibodies from mother across the placenta in the womb. – Child receives antibodies in breast milk. Active Artificial -immunisation from vaccination Passive Artificial -antivenom, bodies response takes too long

Answer 42

Vaccination (immunisation) Injection of deactivated pathogen (attenuated or killed), or toxoid (deactivated form of toxin). Injection still contains the antigen which provokes immune response, but does not cause the infection. Promotes primary immune response, production of memory cells leads to acquired immunity and future protection. Multiple injections (boosters) may be required over short term or long term to increase memory cell number.

Answer 43

Vaccination (immunisation) Injection of deactivated pathogen (attenuated or killed), or toxoid (deactivated form of toxin). Injection still contains the antigen which provokes immune response, but does not cause the infection. Promotes primary immune response, production of memory cells leads to acquired immunity and future protection. Multiple injections (boosters) may be required over short term or long term to increase memory cell number.

Answer 44

light reflex photo receptros when cornea is touched reacting to bright light reflex arc are built in or innate behaviours by passes the brain, but still sends message.

Biology Sem 1 Year 12 Flashcards

(68 cards)