Cell Organisation Flashcards
What is the order that specialised cells form things in?
Cells, tissues, organs, organ systems
What is a tissue?
a group of similar cells that work together to carry out a particular function
What is an example of a type of tissue?
Muscular tissue- contracts, moves what its attached to
Glandular tissue- makes and secretes chemicals (enzymes, hormones)
Epithelial tissue- covers part of the body (inside of the gut)
What is an organ?
a group of different tissues that work together to perform a certain function
What tissues is the stomach made of?
Muscular tissue- moves the stomach wall to churn food
Glandular tissue- makes digestive juices to digest food
Epithelial tissue- covers the outside and inside of stomach
What is an Organ system?
a group of organs working together to perform a specific function
What is the digestive system made up of (organs)?
- Glands (pancreas, salivary- produce digestive juices)
- stomach + small intestine, digests food
- liver, produces bile
- small intestine, absorbs soluble food molecules
- large intestine, absorbs water from undigested food, leaving faeces.
What do organ systems work together to make?
an organism
What are enzymes?
Biological catalysts that speed up useful chemical reactions in the body
Large proteins (chain of amino acids folded into unique shapes)
What is a catalyst?
a substance which increases the rate of reaction, without being changed or used up.
What is an active site?
a unique shape of an enzyme that fits onto a specific substance to catalyse its reaction
How many reactions does 1 enzyme catalyse?
1
What is the lock and key model?
- the active site of an enzyme is specific to a substrate
- the substrate binds to the enzyme, which then allows it to react and breaks off the enzyme
What factors affect enzymes?
- temperature
- pH
What do digestive enzymes break down?
Starch, proteins, lipids (big molecules)
Why do digestive enzymes break down bigger molecules (starch, proteins, lipids) ?
- they are too big to pass the walls of the digestive system
- broken down into smaller molecules like sugars (maltose, glucose), amino acids, glycerol and fatty acids
- now small can be absorbed into the bloodstream
What enzyme breaks down starch into simple sugars?
Carbohydrase (amylase)
Where is amylase produced?
- salivary glands
- pancreas
- small intestine
What enzyme breaks down protien into amino acids?
Protease
Where is protease made?
- stomach
- pancreas
- small intestine
What enzyme breaks down lipids into glycerol and fatty acids?
lipase
Where is lipase made?
- pancreas
- small intestine
What is the role of bile?
- neutralises hydrochloric acid in the stomach (enzymes in small intestine work best at lower pH/ alkaline conditions)
- emulsifies fats-> larger SA of fat, easier for lipase to digest faster
What is the role of the liver?
- Bile is produced
- emulsifies fat
- neutralises stomach acid
What is the role of the gall bladder?
- Bile is stored before being released into the small intestine
What is the role of the large intestine?
- excess water is absorbed from food
What is the role of the rectum?
- faeces is stored before being excreted through anus
What is the role of the stomach?
- pummels food with muscular walls
- produces protease enzyme, pepsin
- produces Hydrochloric acid, kills bacteria + give right pH for protease to work (pH 2)
What is the role of the pancreas?
- produces protease, amylase + lipase
- releases into small intestine
What is the role of the small intestine?
- produces protease, amylase + lipase (complete digestion)
- digestive food is absorbed out of digestive system into blood
Where are the lungs located?
the Thorax
How is the lungs separated from the lower part of the body?
with the Diaphragm
How are the lungs protected?
the Ribcage
How does air reach your lungs?
- breathed in
- through trachea
- splits into 2 tubes, Bronchi
- go into lung through Bronchioles (smaller tubes)
- reach Alveoli (small bags), gas exchange takes place
How do alveoli carry out gas exchange?
- alveoli are surrounded by a network of blood capillaries
- blood passing-> returning from body to lungs= deox, lots of CO2
- oxygen diffuses out of alveolus into blood, CO2 diffuses out of blood into alveolus (breathed out)
How is oxygen carried from the lungs to body cells?
- When blood reaches body cells, oxygen released by Red blood cells + diffuses into body cells
- CO2 diffuses out of body cells into blood, carried back to lungs
What is the double circulatory system?
- made up of the heart, blood and lungs
- double because it passes through the heart twice (once from body, once from lungs)
How does the double circulatory system work?
- right ventricle pumps DEOX blood to lungs, OX blood then returns to heart
- left ventricle pumps OX blood around body to organs, DEOX blood returns to heart, pump to lungs again
What is the heart?
pumping organ, keeps blood flowing around the body
What are features of the heart?
- walls of the heart-> mostly muscle tissue
- valves-> blood flows in correct direction, not backwards
What are the 4 chambers of the heart?
Left atrium, Right atrium, Left ventricle, Right ventricle
How does blood get into the heart?
- Through the vena cava (deox) and pulmonary vein (ox)
- Goes into the atria (left and right atrium)
How does the heart contract to pump blood around the body
- Blood flows into the 2 atria through the vena cava and pulmonary vein
- the atria contract, pushes blood into ventricles
- ventricles contract, forcing blood into pulmonary artery and aorta (out of the heart)
- blood flows to organs through arteries, returns through veins
- cycle repeats, atria fill with blood again
What supplies the heart with oxygenated blood?
Coronary arteries, branch of the aorta + surround the heart
What is a pacemaker?
a group of cells in the right atrium which control resting heart rate
- the cells produce small electrical impulses, spreading to surrounding muscle cells, cause contraction
What is an artificial pacemaker?
controls heartbeat if natural pacemaker cells don’t work (irregular heartbeat).
Device planted under skin, wire into the heart, produces electrical current, keeps regular heartbeat.
What are the 3 types of blood vessels?
Arteries- carry blood away from heart
Veins- carry blood to heart
Capillaries- exchange of materials at tissues
What are the features of arteries?
- pump blood at high pressure, strong + elastic walls
- thick walls, small lumen
- thick layers of muscles (strong) + elastic fibres (stretchy)
What are the features of Capillaries?
- Arteries branch into capillaries
- Tiny
- Carry blood really close to every cell (exchange substances)
- Permeable walls (diffusion)
- Supply food + oxygen, remove waste (CO2)
- 1 cell thick wall, increases rate of diffusion, decreases distance
What are the features of Veins?
- capillaries join up to veins
- lower pressure blood-> less thick walls
- larger lumen-> help blood flow
- valves-> help blood flow in right direction
What is the role of Red blood cells?
carry oxygen from lungs to all body cells
What are features of Red blood cells?
- biconcave shape-> large SA for absorbing O2
- No nucleus-> more room for oxygen
- Red pigment= haemoglobin
How is oxygen transported from red blood cells to body cells?
lungs- Haemoglobin binds to oxygen = oxyhaemoglobin
body tissues- oxyhaemoglobin splits to haemoglobin and oxygen, releases oxygen to cells
How do white blood cells defend against infection
the process of Phagocytosis
OR
Produce antitoxins and antibodies
They also have a nucleus
What is the process of Phagocytosis?
- A phagocyte binds to the cell it wants to engulf
- binds to the cell, surrounds it before engulfing and digesting it
What are platelets and what are their role?
- small fragments of cells, no nucleus
- help the blood clot at a wound (stops blood getting out, microorganisms getting in)
- lack of platelets, excessing bruising + bleeding
What is plasma and what is its role?
- liquid that carries substances in the blood
- red, white cells, platelets
- nutrients (glucose, amino acids- taken to body cells)
- CO2 (organs to lungs)
- Urea (liver to kidneys)
- Hormones
- Proteins
- Antibodies + Antitoxins
What is the role of stents?
Tubes that are inserted inside arteries, keeping them open for blood to pass through -> heart beating + person alive
-lower risk of heart attack for coronary heart disease
- long time effectiveness
- quick recovery time from surgery
-risk of surgery complications + infection
- develop a blood clot (thrombosis)
What is coronary heart disease?
coronary arteries get blocked by layers of fatty material built up.
- arteries become narrow, blood flow = restricted, lack of oxygen to heart muscle
- can lead to heart attack
What is the role of statins?
Drugs that reduce the amount of ‘bad’ cholesterol in the blood, slows down rate of fatty deposits forming
What is cholesterol + its problems
- essential lipid
- too much LDL cholesterol causes fatty deposits inside arteries, leading to coronary heart disease
What are the Advantages and Disadvantages of Statins?
- reduce risk of strokes, coronary heart disease, heart attacks
- increase good/HDL cholesterol, can remove bad cholesterol
- may prevent some other diseases (studies)
- long term drug, has to be taken regularly
-negative side effects (headaches, kidney damage, memory loss, liver failure) - takes time for effect to kick in
What is an artificial heart?
a mechanical device that pumps blood for a person whose own heart has failed
- normally used until a donor heart can be found, can be used as permanent solution, reduced donor heart demand
What are advantages and disadvantages of artificial hearts?
- less likely to be rejected than donor (metal or plastic, unrecognised as foreign)
- surgery risks + complication + infection
- don’t work as well as healthy hearts (parts could wear out)
- blood doesn’t flow as smoothly, causes blood clots, leads to strokes
- blood thinners, causes bleeding problems if in accident
What are biological valves?
valves taken from humans or other mammals (cows or pigs)
What are mechanical valves?
man made valves
Why are mechanical and biological valves used?
- heart valves can be damaged/weakened by heart attacks, infection, old age
- causes valves to stiffen, won’t open properly
- leaky valves, blood flows in both direction (inefficient circulation)
- less drastic procedure than whole heart transplant, still major surgery + blood clot issues
What is artificial blood?
blood substitute, used to replace lost volumes of blood
otherwise need a blood transfusion
How can different diseases interact?
- increased immune system issues-> increase chances of suffering from communicable diseases (ie flu). Body is less likely to be able to defend itself against disease pathogen
- some cancer can be triggered by certain virus infections (HPV-> cervical cancer)
- immune system reactions by disease infection triggers allergic reactions (skin rashes, worsen asthma)
- Mental health issues triggered by physical health problems (impact of everyday life, life expectancy)
What is a pathogen?
an organism that causes a disease
What factors affect health?
- balanced diet
- stress
- access to medical care, food, condoms
What are risk factors for non-communicable diseases? (increase chances of disease)
- lifestyle (exercise)
- environment (air pollution)
- diet
What risk factors directly cause a disease?
- smoking (lung disease, lung cancer)
- obesity (type 2 diabetes)
- alcohol (liver damage)
- smoking when pregnant (health problems for unborn baby)
- exposure to substances/ radiation (cancer from carcinogens, ionising radiation)
What is cancer caused by?
uncontrolled cell growth and division
What does a benign tumour mean?
the tumour stays in one place (within a membrane)
- not really dangerous, not cancerous
What does a malignant tumour mean?
tumour spreads and grows to neighbouring healthy tissue, spread through the bloodstream, invade healthy tissues elsewhere + form secondary tumours.
- can be dangerous + fatal, are cancerous
What are risk factors associated with lifestyle?
- smoking
- obesity
- UV radiation
- Viral infection
What are risk factors associated with genetics?
- inherited faulty genes, more susceptible to cancer
- mutation-> increased chance of developing breast + ovarian cancer
What are examples of plant organs?
stems, roots and leaves
What are examples of plant tissues?
Epidermal tissue- covers the whole plant
Palisade mesophyll tissue- most photosynthesis happens
Spongy mesophyll tissue- big air spaces for gas diffusion in and out of cells
Xylem and Phloem- transport water, mineral ions, food
Meristem tissue- growing tips, shoots, roots, differentiate to different types of plant cells, growth
What plant tissues do leaves contain?
epidermal, mesophyll, xylem, phloem
What are the layers in a leaf?
Top to bottom:
- waxy cuticle
- Epidermal tissue
- Palisade mesophyll tissue
- Xylem and Phloem
- Spongy mesophyll tissue = AIR SPACES
- Epidermal tissue
- Stomata + Guard cells
What are the functions of structures in a leaf?
- Epidermal tissues-> waxy cuticle, reduces water loss
Upper epidermis-> transparent so light can pass through to the palisade layer
Palisade-> lots of chloroplasts, near top of leaf, photosynthesis
Xylem + Phloem-> deliver water + other nutrients to entire leaf, take away glucose (photosynthesis), support the structure
Tissues-> adapted for efficient gas exchange (stomata)
What is the role of the Phloem?
Transports food
- made of columns of elongated living cells, small pores in end walls, allow cell sap to flow through
- transport food substances (dissolved sugars) from leaves to rest of plant for immediate use or storage
- TRANSLOCATION
What is translocation?
Transport of dissolved sugars around a plant within the Phloem
What is the role of the Xylem?
Take water up
- made of dead cells joined end to end, non end walls, hole in the middle, strengthened by lignin
- carry water + minerals from roots to stem and leaves
- movement of water from roots, through Xylem, out of leaves
- TRANSPIRATION
What is Transpiration?
The movement of water from the roots through the Xylem out of the leaves
- caused by evapouration and diffusion
What is transpiration rate affected by?
- Light intensity: brighter light= greater rate
- Temperature: warmer= faster rate
- Air flow: better air flow=greater rate
- Humidity: drier the air= faster rate
How are Guard cells adapted to open and close Stomata?
- kidney shape-> open + closes stomata
- more water in plant-> guard cells fill + go turgid, stomata open, gases exchange for photosynthesis
- less water in plant-> guard cells lose water, go flaccid, stomata close, stops water vapour escaping
- thin outer walls, thickened inner walls-> makes opening and closing work
- sensitive to light-> close at night, save water without losing on photosynthesis
- lower surface of leaf-> cooler, less water is lost, more stomata
What are guard cells adapted for?
- Gas exchange
- controlling water loss
