EOY 10 Exams Flashcards
(79 cards)
1
Q
What is the function of the mouth in the alimentary canal?
A
- salivary glands produce amylase, which breaks down starch and lubricates food
- performs mechanical digestion
2
Q
What is the function of the oesophagus in the alimentary canal?
A
- transports food from mouth to stomach by peristalsis*
(the oesophagus has two layers; circular muscle layer and longitudinal muscle layer)
*the constriction and relaxation of the muscles of the oesophagus, pushing the contents of the canal forward.
3
Q
What is the function of the stomach in the alimentary canal?
A
- Contains HCL for the chemical breakdown of food
- To kill bacteria
- Provide an optimum pH for enzyme activity
- Churns food into chyme*
- the acidic fluid which consists of gastric juices and partly digested food.
4
Q
What is the function of the small intestine in the alimentary canal?
A
- the duodenum* breaks down foods using enzymes and adds bile
- the ileum** absorbs nutrients into the bloodstream
- the first part of the small intestine immediately beyond the stomach
- the third portion of the small intestine
5
Q
What is the function of the large intestine in the alimentary canal?
A
- the colon* absorbs water from waste products into the bloodstream
- the rectum** stores food, which is later removed through the anal sphincter***
- part of the large intestine, the final part of the digestive system
- the final section of the large intestine, stopping at the anus.
- ** a group of muscles at the end of the rectum that surrounds the anus and controls the release of stool
6
Q
What is the function of the pancreas in the alimentary canal?
A
- contains exocrine glands that produce enzymes
7
Q
How does peristalsis work?
A
- When the circular muscles contract and the longitudinal muscles relax the gut is made narrower
- When the longitudinal muscles relax and the circular muscles contract the gut is made wider
- Waves of contraction pass along, pushing the food down; circular waves push behind the bolus, longitudinal waves push down the bolus
NOTE: movement of food down the oesophagus does not depend on gravity
8
Q
What is bile?
A
- green liquid stored in the gall bladder
- passed down the bile duct
- doesn’t contain enzymes
- is alkaline (as to neutralize acidic contents of the stomach)
9
Q
How does bile neutralize stomach acid?
A
- The mixture of semi-digested food and enzymes from the stomach is acidic, and bile is alkali
- Neutralizes the contents so that it is safe for the rest of the organs to absorb/come into contact with
10
Q
How does bile emulsify lipids?
A
- Bile turns any large lipid globules into an emulsion of tiny droplets
- Increases the surface area of the lipid so lipases can break it down easier
*Emulsification = to break up into smaller parts
11
Q
What are the different digestive enzymes and their roles?
A
CARBOHYDRASE
- Amylase produced in the salivary gland works in the mouth and turns starch into maltose
- Amylase produced in the pancreas works in the small intestine and turns starch into maltose
- Maltase produced in the wall of the small intestine works in the small intestine and turns maltose into glucose
PROTEASE
- Pepsin produced in the stomach wall works in the stomach and turns proteins into peptides
- Trypsin produced in the small intestine works in the pancreas and turns proteins into peptides
- Peptidase produced in the wall of the small intestine works in the small intestine and turns peptides into amino acids
LIPASE
- Lipase produced in the pancreas works in the small intestine and turns lipids into glycerol and fatty acids
12
Q
What are the different layers of the villi?
A
(from the outside inward)
- Microvilli
- Epithelial cells
- Capillary
- Lacteal
NOTE: the blood diffusing through comes from the mesentery artery and is transferred to the hepatic portal vein
13
Q
What is assimilation?
A
Soluble food molecules absorbed from the blood into the cells of tissues and used to build new parts of cells
14
Q
How is the small intestine adapted for absorption?
A
LARGE SURFACE AREA
- length of intestine
- folds into its lining
- tiny projections in the lining called villi
15
Q
What is the function of the capillary in the villi?
A
- transports amino acids and glucose
16
Q
What is the function of the lacteal in the villi?
A
- transports fatty acids and glycerol
17
Q
How do villi work?
A
- Increase surface area and the microvilli increase it further
- All the nutrients pass through the epithelial layer and into the lacteal and capillaries to be transported around the body
18
Q
Describe the practical; enzymes affected by temperature changes
A
- spots of iodine put on a dimple tray
- amylase solution and the starch solution heated up then mixed together
- add a drop to iodine solution and record color every 30s for 10 minutes
- repeat with different temperatures
- could see when the starch solution had been broken down by color change
- the time this took was the rate of reaction
19
Q
Define optimum
A
- the best temperature at which the reaction takes place the fastest
- rate of reaction can be increased by raising the concentration of enzyme or substrate
20
Q
What temperature do enzymes in the body work at?
A
37 degrees Celcius
21
Q
How does temperature affect enzymes?
A
- As the enzyme is heated up to its optimum temperature, the rate of reaction increases; this is because of higher temperatures give molecules of enzymes and substrates more kinetic energy so they collide more often
- As the temperature begins to increase above the optimum the rate of reaction begins to decrease; this is because enzymes are made of protein and protein is broken down by heat above 40 degrees Celsius
^^ The destroying of an enzyme is called denaturing; when the shape of the active site of an enzyme changes so that the substrate can no longer fit into it
- This is permanent; enzymes can no longer catalyze
22
Q
Improve the practical; enzymes affected by temperature changes
A
- recording the color changes at shorter intervals
- use a water bath; presents temperature from dropping as the experiment goes on
- measure the temp of the solution rather than just the water
23
Q
How to calculate energy (in joules) per gram
A
change in temperature x volume of water x 4.2 / mass of food
24
Q
Describe the practical; the energy content in a food sample
A
- mass of food sample
- a measured volume of water in a boiling tube
- temperature of water recorded
- food spread on the end of mounted needle
- held in bunsen burner until it catches fire
- hold burning food underneath the boiling tube
- when food will no longer burn measure the temperature
25
How does a calorimeter work?
- it is filled with oxygen, so food burns easily
- it is lighted/heated by a heating filament carrying an electric current; does not give any extra heat as a bunsen burner does
- stirrer to equalize heat in the water
- in a sealed container; reduces heat loss by wind
- electrical wire; don't have to transfer from bunsen burner so no loss of heat
26
pH's of the mouth, stomach, and small intestine
mouth - 7
small intestine - 8
stomach - 2.5/3
27
Describe the practical; enzymes affected by pH changes
- potato mixed in blender; to release catalase from cells
- mix of potato extract, buffer solution, and catalase
- hydrogen peroxide solution added and bung and delivery tube inserted
- bubbles of O2 produced in the first minute are counted
28
Improve the practical; enzymes affected by pH changes
- use a gas syringe instead of counting bubbles
- repeat using the same buffer
- control the temperature by using a water bath
29
What are the three things required for diffusion?
- steep concentration gradient
- short diffusion pathway
- moisture
30
What adaptations do alveoli have for gas exchange?
- spherical shape; increased surface area
- large quantities and very tiny; increased surface area
- thin walls (1 cell thick); short diffusion pathway
- moist surface; goof for diffusion as gasses can dissolve
- good blood supply from capillaries surrounding; maintains concentration gradient by removing O2 and bringing lots of CO2
31
How many membranes does oxygen have to pass through in the alveoli?
5
32
Describe the process of gas exchange in the alveoli
- deoxygenated blood from respiring tissues is pumped from the heart to the lungs
- oxygen diffuses into the capillary - combines with haemoglobin in red blood cells - producing oxyhaemoglobin
- carbon dioxide diffuses into the aleolus
- blood that leaves capillaries lost CO2 and gained 02; it now is oxygenated
- heart pumps it back around body to respiring cells
33
How is ATP made?
- oxygen oxidizes food and produces CO2 + H2O as waste products
- energy from this reaction used to add a phosphate to ADP (Adenosine diphosphate) to make ATP (Adenosine triphosphate)
34
What is the energy in ATP used for?
- contractions of muscle cells (movement)
- active transport of molecules and ions
- building large molecules (e.g. protein)
- cell division
35
What is cellular respiration?
the breakdown of glucose and other respiratory substances to make energy molecules called ATP
36
What is diffusion?
- the net movement of particles from a region of high concentration to a region of low concentration
37
What is osmosis?
- the net movement of water from a dilute solution to a more concentrated solution across a semi-permeable cell membrane
38
What is active transport?
- The movement of substances against a concentration gradient using the energy produced in respiration
- e.g. glucose absorbed by cells lining the intestine; used in cells to control the uptake of substances
39
Why does diffusion occur?
- because of the kinetic energy of the particles
- does not require any extra energy
- occurs in cells during gas exchange
40
When does osmosis occur?
- when total concentration of dissolved substances inside and outside of the cell are different
- how 'free' water molecules move is called "water potential"
41
What effects does nicotine have on the body?
- increased bowel activity, saliva, and bronchial secretions
- tremors and convulsions; stimulates the nervous system
- sweating
- nausea
- diarrhea
42
What are some health risks of taking in nicotine?
- blood cloths
- high blood pressure
- delayed wound healing
- issues with pregnancy
43
What are the risks of second-hand smoke?
IN ADULTS
- sudden/severe reactions
- coronary artery disease
- lung cancer
IN CHILDREN
- asthma
- infections
- poor lung function
- SIDS
44
Link smoking to lung cancer
- smoke contains over 700 chemicals; 60 have been known to cause cancer
^ these chemicals are called carcinogens
NOTE: cancer happens when cells mutate uncontrollably, forming a tumor
45
Describe chronic bronchitis
- tar and chemicals paralyze the cilia - can't get rid of bacteria
- more chest infections + mucus remains + blocks air passage
- smoke irritates the lining - stimulate cells to secrete more mucus
- mucus blocking airway causes smokers cough
- irritation of bronchial tree and bacteria causes bronchitis
46
Describe emphysema
- smoke damages alveoli walls; they break down and fuse together
- this forms large, irregular air spaces and alveoli become flattened
- reduces the area for gas exchange; their blood carries less oxygen so people are often left out of breath
- mucus/fluid could also fill alveoli which reduces gas exchange
47
Describe coronary heart disease (CHD)
- fatty deposits in the walls of coronary arteries cut off the blood supply to the heart and can cause heart attacks
- CO2 from smoke interferes with 02 ability to bind with haemoglobin - it binds with CO2 instead and produces carboxyhaemoglobin
- The heart has to beat faster with a higher pressure; damage to artery walls make clots more likely
- Nicotine also makes blood cells more sticky and narrows blood vessels (vasoconstriction)
48
Describe the practical; release of CO2 in humans
- used to compare the volume of CO2 in inhaled and exhaled air
- limewater in the exhale tube will turn cloudy before the limewater in the inhale tube because we exhale more CO2 than we inhale
49
Describe the practical; effect of exercise on breathing in humans
- sit for 5m and measure breathing rate (resting rate)
- do exercise
- immediately after, sit down and measure breathing rate again
- continue to record until you reach your resting rate
- breathing rate increases because muscles need more energy to move; need more O2 to respire; need to breathe more frequently
50
What are the characteristics of living organisms?
- movement; move to get food and away from danger
- respiration; releasing energy taken in from glucose
- sensitivity; responding to stimuli
- growth; to increase in size
- reproduction; to make more of the species
- excretion; to remove bodily waste
- nutrition; to take in nutrients that are necessary
- homeostasis; controlling your internal environment
51
What is a eukaryotic organism?
Organisms whose cells have a nucleus enclosed within membranes
52
Describe four eukaryotic organisms
PLANTS
- multicellular
- the cell wall is made of cellulose
- have chloroplasts to carry out photosynthesis
- carbs stored as starch or sucrose
- e.g. herbaceous legume (peas or beans)
ANIMAL
- multicellular
- no cell wall
- have nervous coordination; can move
- carbs stored as glycogen
- e.g. mammals (humans)
FUNGI
- organized into a mycelium made from hyphae
- single-celled
- cell walls made of chitin
- extracellular secretion of enzymes onto food and absorption via the saprotrophic process
- carbs stored as glycogen
- e.g. (as a hyphal structure) Mucor, (single-celled) Yeast
PROTOCTISTS
- microscopic
- single-celled
- some have a cell wall, some don't
- some live in pond water, have animal features; others are like plants with chloroplasts
- carbs are stored as glycogen or starch/sucrose
- e.g. (animal-like) amoeba, (plant-like) chlorella, (pathogen) Plasmodium; causes malaria
53
What is a prokaryotic organism?
A unicellular organism that has no membrane-bound organelles
54
Describe a prokaryotic organism?
BACTERIA
- microscopic
- single-celled
- have a cell wall, cell membrane, cytoplasm, plasmids
- have no nucleus, but have a circular chromosome of DNA or RNA
- some carry out photosynthesis but most feed off other living or dead organisms
- e.g. lactobacillus bulgarius (used to make yogurt), pneumococcus (pathogen causing pneumonia)
55
What is a pathogen?
A micro-organism that can cause disease
56
Describe an example of a pathogen
vIRUS
- a not ling organism
- smaller than bacteria
- parasitic; can only reproduce inside living cells
- have a wide variety of shapes and sizes; no cellular structure
- e.g. tobacco mosaic virus (causes discoloring of tobacco leaves; prevents the formation of chloroplast), influenza virus (causes the flu), hiv virus (causes AIDS)
57
What is a parasite
- lives off of other organisms without giving the host any benefits
58
Describe a virus cell
- much smaller than bacteria cells- are NOT made of cells; no nucleus, cell wall, cytoplasm, etc.
- composed of a core of genetic material surrounded by a protein coat
- are parasitic; can only reproduce inside living cells
- the border between an organism and a non-living chemical
- the only trait of MRS GREN they have is reproduction -which they do parasitically
- reproduces by entering the host cell, taking over genetic material to make more virus particles
- after many are made, host cell dies and particles released to infect other cells
- taken into a cell, inject genetic material, make copies > produce a lot of protein, host cell bursts and dies
- contains an envelope, protein coat, and DNA/RNA
59
Describe a bacteria cell
- cell wall made of peptidoglycan
- has no nucleus; stores genetic material in a single chromosome
- some bacteria contain chlorophyll
- bacteria need protein for things like repairing damage and directing chemical processes
- many bacteria are decomposers; recycling dead organisms and waste products
- some can move and respond to a large range of stimuli
- includes a cell wall, cytoplasm, plasma membrane, DNA, pili, ribosomes, flagellum, a plasmid, and a capsule
60
What is an autotroph versus a heterotroph
HETEROTROPH
- cannot make their own food
- consume nutrients from other organisms
- conduct external digestion (saprotrophic process)
- reproduce sexually and asexually
- can be used to fight bacterial diseases (NOT viruses)
AUTOTROPH
- Can make their own food using light, water, carbon dioxide or other chemicals
61
What does hypertonic mean?
- the concentration of solutes is greater/ water potential is less outside the cell
- the cell is flaccid; cell loses water, decreases in volume and cytoplasm no longer pushes against the cell wall
62
What does isotonic mean?
- solutions on the inside and outside have similar/the same concentration
63
What does hypotonic mean?
- the concentration of solutes is greater/ water potential is less inside the cell
- the cell is turgid; cell absorbs water, swells up, develops internal pressure, cytoplasm pushes against the cell wall
64
What is aerobic respiration?
- requires oxygen
- occurs in mitochondria
- glucose is completely broken down
- produces CO2 and H2O
- produces 19x more energy
65
What is anaerobic respiration?
- does not require oxygen
- occurs in the cytoplasm
- glucose not completely broken down
- muscle yells; lactic acid produced
- plants; ethanol and CO2 produced
- produces less energy
66
What is the word and balanced chemical equation for aerobic respiration?
1. glucose + oxygen --> carbon dioxide + water + energy
| 2. C6H12O6 + 602 --> 6CO2 + 6H2O + ATP
67
What is the word and balanced chemical equation for anaerobic respiration in plants?
1. glucose --> ethanol + carbon dioxide + little energy
| 2. C6H12O6 --> 2C2H5OH + 2CO2 + ATP
68
What is the word and balanced chemical equation for anaerobic respiration in muscles?
1. glucose --> lactic acid + energy
| 2. C6H12O6 --> 2C3H6O3 + ATP
69
Why does anaerobic respiration occur in muscle cells?
- when muscles are overworked; blood can't reach them fast enough to deliver 02
- only provides enough energy to keep the overworked muscle going for a short period
- lactate levels rise in the muscles and bloodstream; you get tired
- the oxygen that builds up in the body needed to oxidize lactate during anaerobic respiration is called oxygen debt
70
What are the three main types of stem cells?
- EMBRYONIC STEM CELL; come from embryos 3-5 days old. harvested during a process called in vitro fertilization and can differentiate into any cell type
- ADULT STEM CELL; found in developed adult tissues (e.g. bone marrow, skin, intestine lining) and cannot differentiate into different cell types but may form specialized tissue.
- CORD BLOOD; harvested from the umbilical after birth and stores for future use.
71
What are the advantages of using stem cells?
- help scientists to learn about growth and development
- used to research how diseases occur and how to treat them
- new cells can be grown to use as transplants for damaged limbs and organs
- able to test potential medicines without testing on animals/humans
72
What are the disadvantages of using stem cells?
- long term effects are unknown
- embryonic stem cells may not be the solution for diseases
- stem cells are derived from a separate body than the patient, so the patient's body could reject them
- lab-fertilized eggs are considered human life, so some find this immoral
73
How do energy requirements vary with activity levels, age, and pregnancy?
- a person who has quite a high energy level and works all day will need more energy than a person with a sedentary lifestyle
- young people need to eat more/have more energy has their bodies are growing
- loss of blood through menstruation in young woman can cause anemia; producing a need for iron
pregnant women will need a higher energy intake, as they are eating for two people - they also need more iron and calcium for the growth of their baby
74
Describe the vitamins and minerals found in the body
VITAMIN A
- sourced in fish liver oils, butter, margarine, and carrots
- makes a chemical in the retina that protects the surface of the eye
- deficiency causes night blindness, damaged cornea
VITAMIN C
- sourced in fresh fruit and vegetables
- sticks together cells lining surfaces e.g. mouth
- deficiency causes scurvy (unhealing wounds, bleeding gums)
VITAMIN D
- sourced in fish liver oils, added to dairy products, made in the skin in sunlight
- helps bones absorb calcium and phosphate
- deficiency causes rickets, poor teeth
CALCIUM
- sourced in dairy products, fish, bread, vegetables
- makes teeth and bones, makes muscles contract, synaptic transmission in nerves
- deficiency causes weak/poor bones and teeth
IRON
- sourced in meat, liver, eggs, dark leafy greens
- part of haemoglobin in red blood cells; helps carry oxygen
- deficiency causes anemia (not enough 02 going around the body)
75
What factors affect the rate of osmosis/diffusion?
- concentration gradient; steep increases rate
- surface area; larger increases rate
- diffusion pathway; shorter increases rate
- temperature; higher increases rate
76
What factors affect active transport?
- o2 concentration; higher increases rate
- glucose concentration; higher increases rate
- temperature; optimum for enzymes increases the rate
- speed of protein carriers; high increases rate
77
Describe the practical: diffusion and osmosis in agar jelly
- cubes of different sizes are dropped into beakers od dilute HCL
- time for each cube to turn colorless is recorded
- the smallest cube turns colorless first; has the largest surface area to volume ratio
78
Describe the practical: diffusion and osmosis in onion epidermis cells
- a drop of sucrose solution and are of distilled water and are put on two slides
- a small square of the inner epidermis is put on each slide
- done quickly so that the cells do not dry out
- the slides are examined for some time; cells in the water go turgid
79
Describe the practical: diffusion and osmosis in potatoes
- pieces are put in distilled water, sucrose solution, and nothing
- distilled water increases mass, sucrose solution decreases mass,
