Biology (organisms)

lineaus concept

Species are organisms with similar or shared morphological characteristics

binomial nomenclature

Genus +species

biological species

organsism that are able to breed and produce fertile offspring

n of human and chimp chromosomes

humans have 46 , chimps 48

karyogram

a visual representation of homologous chromosomes ordered by size

theory of chimps and humans

believed that humans evolved from chimps, chromosome 12 and 13 of chimps fused to form human chromosome 2

evidence:

• placed end to end are similar in size

• telomeric DNA found wihtin human chromosomes

• satelite DNA found in centromeres, found within chromosome 2 at the position of chromosome 13

whole genome sequencing and uses

when they can view an organisms full genome sequence

can be used to study evolutionary relationships and also for personalized medicine, administering right dose and formula, limiting effects and maximizing treatement

what organisms is the biological species concept difficult to apply to

organisms that can reproduce asexually and organisms that undergo horizontal gene transfer

dichotomous key

a series of yes or no questions based on morphological traits that can be used to determine species

DNA barcoding and uses

Genome sequences are given a BIN, which is put into a database. Environmental DNA can be taken and tested in the database for what species are present

can work as indicator for pollution due to some organisms being very sensitive

levels of classification

kingdom, phylum, class, order, family, genus, species

phylogeny

study of evolutionary past

clade

group of organisms with common ancestry

cladistics

study of evolutionary relationships based on genetics and shared traits

primitive traits

traits that evolved early on

derived traits

traits that evolved more recently

moleuclar clock

a technique where it can be predicted how how ago organisms evolved using, DNA hybridization,

take DNA of two 2 organisms and fused them together, see how many differences, can estimate how long ago they evovled form each other

cladogram

shows the divergence of clades, using amino acid and genetic sequences

parts of cladogram

• clade

• root; the first common ancestor that all evolved from

• node: the point of speciation

• terminal branch: last speciation

reclassification

figwort family: plants put into this classification based on morphological features, later found not to be related

3 domains

Archaea, eubacteria, Eukaryota

properties of gas exchange surfaces

thin, moist, large SA, permeable

how are gradient maintained in blood

dense network of blood vessels and continuous blood flow

adaptations to mammalian lungs

• extensive branching of bronchioles

• extensive capillary beds around alveoli

• many alveoli providing large SA

what happens during inhalation

diaphragm contracts, moving down, pressure decreases and volume increase, causing air to enter. internal intercostal muscle relax, external intercostal muscle contract

what happens during exhalation

diaphragm relaxes, decreasing volume and increasing pressure, air moved out of lungs, external intercostal muscles relax, internal intercostal muscles contract

different types of measurements for lung volume

tidal: volume in and out at rest

inspiratory volume: volume of air that can be added after tidal

expiratory volume: volume of air that can be exhaled after tidal volume

vital: the volume exhaled after a maximum inhalation

leaf structure

• waxy cuticle

• upper epidermis

• palisade mesophyll

• vein: phloem, xylem

• spongy mesophyll

• stomata

• guard cells

• lower epidermis

waxy cuticle

covers the surface and prevents uncontrolled and excessive leaf water loss by evaporation

upper epidermis

secretes waxy cuticle

palisade mesophyll

cylindrical cells densely packed with many chloroplasts to maximize sun light absorption

spongy mesophyll

few chloroplasts but space between allowing large SA for gas exchange

lower epidermis

small cells on lower surface of leaf that secrete waxy cuticle

stomata

openings that control gas exiting and entering, and water loss

what is transpiration

evaporation of water from open stomata

effected by:

• light intensity

• temperature

• humidity

• wind speed

how to measure stomata density

n of stomata/ area in view

functioning of haemoglobin

has 4 iron groups which is where O2 can attach, when an O2 binds it increases affinity for O2, making it easier for the next one the bind

• CO2 can also bind to alloasteric site causing a conformational change, decreasing the affinity for O2

adult haemoglobin

2 alpha and 2 beta polypeptides, lower affinity for oxygen, higher affinity for BPG, which competes with O2

foetal haemoglobin

2 alpha and 2 gamma polypeptides, high affinity for O2

what are capillaries

smallest of blood vessel, connecting veins and arteries for exchange of materials

adaptations of capilaries

• large SA due to being highly branched

• thin walls

• small inside diameter

adaptations fo arteries

arteries are responsible for bringing blood away from heart

• blood under high pressure, requires thick walls to withstand pressure

• walls filled with elastin and collagen, with surge of blood fibres can stretch to accommodate pressure

• once blood surge is complete they can recoil, propelling blood forwards

• smooth muscle

adaptations to veins

veins are responsible for delivering blood to the heart

• blood pressure is very low and slow-moving

• has valves to prevent backflow of blood

• surrounding muscles contract opening valves and pushing blood forward.

• walls are highly flexible

where can you measure pusle

• neck: carotid artery

• wrist: radial artery

occlusions of coronary artery

blockage in the coronary artery delivering blood to cardiac muscles

• can be due to build up of cholesterol or other substances causing plaque, preventing flow of blood

• can result in heart attack due to lack of oxygen to cardiac muscles

transport of water during transpiration

when water leaves through stomata during transpiration, due to cohesion and adhesion, water moves in a continuous flow, from roots to shoot, pulling water molecules up towards transpiring tissue

adaptations of xylem

xylem is a dead hollow cell responisbel for transport fo water

• walls are with lignin; provides stability and rigidity to withstand pressure

• pits to allows for lateral movement of water

Draw and label a transverse section of the stem

draw and label transverse section of the root

tissue fluid + lympatic system

fluid that is created through pressure filtration in the arterial side, due to high pressure, smaller molecules and plasma escape into spaces between capillary beds, can exchange with cells, on the venule side where low pressure, tissue fluid can re-enter the capillary bed

the tissue fluid that cannot enter back into capillary beds, enters the lymphatic system, where it is filtered and eventually returned back to the bloodstream

double circulatory system vs single (diagram)

in the double ciruclatory system , blood regains pressure when it reaches the heart, to provide enough pressure to send blood through body

motile organism adaptations

• organisms that move from one from to another actively

brown throated three toed sloth:

• very slow moving organisms

• once a week drop to ground and drop to gorund to defeacate, leavin gbehind half of muscle mass

• three long toes adapted for hanging

sessile organisms adaptations

sessile: stationary cant actively move from place to palce

venus fly trap:

• soil deficient in minerals

• trap has shrot trigger hair when something lands, it closes to prevent it from escaping

sacromere

actin (thin) and myosin (thick) filaments, that slide over each other, muscles are made up of many sacromeres

how do sacromeres move

myosin heads are phosphorilated causing. change in position of the heads, —> attarcted and attach to binding site on actin filament, forming cross bridges, phosphate released) —> as ADP is released, mysoin bends due to loss of energy, bending occurs towards the centre of sacromere and actin moves inwards —> myosin binds to ATP allowing myosin heads to dettach from actin

titin and its role

titin is a spring like protein attached to the myosin z line, preventign overstreching of sacromere and recoiling

antagonistic muscles + example

muscles that accomplish opposite movements

• external and internal intercostal muscles:

  • during ihalation: internal muscles relax and external contract moving ribcage up

tendons

connective tissue between muscle and bone

synovial joint

when theirs 2 bones that need to move against each other and require a large range of motion

components of synovial joint + example

cartiledge: covers both to protect bone to bone contact

synovial fluid: lubricatign fluid that reduces friction

ligament: encircles joint to keep bones in place

tendon: coonnects muscles to bones

femur and pelvis

locomotion

ability to move from one place to another

adaptations for swimming in marine mammals

for example dolphins:

• streamlined shape; minimum drag in water

• nearly no body hair: limit drag

• tail has fluke: up and down motion to move forward

• lsot real legs.

• blowhole for air

• can stay under water for long periods of time—> deep dives

adaptations of mammalian heart

·       cardiac muscle

·       Pacemaker: also known as the SA node: sends electric impulses controlling cardiac cycles

·       ventricles: work to pump blood into the arteries: thick muscle

·       atrium: receives blood from veins at low pressure thin muscle wall

·       coronary vessels: work to provide oxygenated blood to the cardiac muscle

·       semilunar valves/pulomary valves: prevetn back flow of blood into ventricles

How does the cardiac cycle work

·       controlled by the SA node (pace maker)

·       SA node sends action potential/ impulse to atria, causing them to undergo systole, pushing blood into ventricles—> Impulse reaches AV node which sends it own action potential down purkinje fibres and bundle of his, surrounding the ventricle, casuing them to undergo systole, pushed into arteries

  generation of xylem root pressure

if water needs of plants are insufficient, through active transport their can be movement of ions into the root hairs —> decreasing water potential —> drawing water into root hairs

hierarchy of subsystems starting with cells

cells —> tissues —> organs —> body systems —> organisms

emergent features

features that exist only due to the accumulation of all different components

An example of integration between endocrine and neural signalling

epinephrine production:

sensory neurons transmit to CNS that epinephrine is needed —> ANS sends impulse to Adrenal gland to produce epinephrine

what does the brian act as

as a place for processing, storing and reciving information

components of Nervous system

• CNS

• spinal chord

what is spinal chord responsible for

integrated centre founconcious processes

grey and white matter, most occurs in the grey matter

series of events from receptor to effector

sensory receptor recives a stimulus gathers info —> sensory neuron —> CNS or spinal chord —> motor neuron —> effector organ

what are nerves

bundles of nerve firbes surrounded by a protective sheath, containing sensory adn motor neurons

reflex arc

involuntary and rapid response to stimulus

receptor —> sensory neuron —> inter neuron —> motor neuron —> effector organ

cerrebelum

coordination centre for muscle contrations

balance, posture, things that require muscle memory

melatonin

hormone that control circadian rhythm; sleep and awaek cycle/patterns

inhibited by light

promotes drowsiness, sleep

uses sensory neuron in the eye

epinephrine use + effects

used for vigorous activity, icnreasing O2 and glucose contents

• hydrolyzes glucose

• increases ventilation rate

• increases blood flow

control of heart rate

SA and AV node are connected to the medulla

• chemoreceptors; located in aorta and carotid wall sense pH,

  • low pH, means high CO2 concentration

  • increase HR

• baroreceptors: sense BP in aorta, located in walls of blood vessels

control of ventilation rate

monitored by chemoreceptors in the brainstem

• if CO2 is high in blood stream, pH low, ventilation increases to remove CO2

• If CO2 is low in blood stream, pH high, ventilation decreases

peristalsis + which parts of digestion are controlled and not

muscle contracts that move food through digestive tract

• controlled by CNs and consciously: defectating later in life, swallowing, chewing

• controlled by ENS, involuntary: peristalsis and defecation early in life

what is tropism and what types are their

tropism: growth in response to stimuli

• positive: towards the stimuli

• negative: away from stimuli

positive phototropism

growth towards light, requires their to be rapid growth on side in shade in order to grow towards light

phytohormones

signalling chemicals responsible for growth, development and response to stimuli

auxin

a phytohormone responsible for tropism

• cells must coordinate in order to gather auxin in high concentrations, to where it needs to be

• use of auxin efflux carriers: transmembrane proteins that pump auxin into cell

• auxin works by activating pumps that pump h+ across, allowing thier the be a decrease in pH, more acidic —> weakening of cell wall bonds, allowing for elongation

cytokinin vs auxin

auxin: works from shoots to roots

cytokinin: works from roots to shoots

they work together in order to ensure equal growth of root and shoot

fruit ripening

occurs through ethylene, which is a hormone in a gaseous state

• it ripens fruits —> which consequently produces more ethylene further ripening fruits —> as it is a gas also effects neighbouring fruits

pathogens

disease causing organisms

primary defense system

skin, mucus act as barrier

how does blood clotting work

platelets gather at open wound —> form a plug —> release of clotting factors —> convert prothrombin to thrombin —> converts fibrinogen (insoluble) to fibrin (insoluble) —> forms mesh/net at wound —> trap red blood cells, platelets, plasma —> forming blood clot

innate immune system

immune system immune system you’re born with recognises self and not self, what youre born with

adaptive immune system

immune system that develops over life time from exposure to pathogens

phagocytes

white blood cells capable of amoeboid movement, when an antigen is encountered it engulfs it through endocytosis —> enzymes in lysosome breaks down pathogen (non specific)

B- Lymphocytes

Produce antibodies

bind to antigens, to be recognised to be broken down (forms clumps recogized by phagocytes)

what could presence of antigens possibly lead to + blood example

The presence of antigens may stimulate antibodies to be produced

if erythrocyte with antigens are put into blood stream, antibodies will be produced causing clumping of blood

how do t helper cells work

they work by signalling to b lymphocytes to produce antibodies

• happens as T helper cells recognize antigens on pathogen, activating to helper cells, producing cytokines which consequently causes b lymphocytes to produce antibodies

cloning of B lymphocytes

Once B-lymphocytes are activated, they undergo mitosis to clone themselves, producing b-plasma cells. These b-plasma cells then secrete large quantities of specific antibodies.

immunity

adaptive ability to produce antibodies to fight off infections

memory cells and immunity

B-cells differentiate into memory cells, which remain in the bloodstream (and lymphatic system). Upon secondary exposure to the same pathogen, memory cells quickly recognize the antigen and trigger a rapid, stronger immune response

transmission of HIV

Human immunodeficiency virus

transmitted through bodily fluids

• unprotected sex

• sharing hypodermal needles

• transfusion of blood

• birth/breast feeding

what is HIV and how does it work

destroys T helper cells, which limit the B cells activated, limiting antibodies produced —> more vulnerable to pathogens

HIV develops into AIDS, where their is 0 ability to produce antibodies —> cannot fight any infections or diseases anymore