2. Structure and functions in living organisms (2a-e) Flashcards
1
Q
What are organelles?
A
A component within a cell that carries out a specific task
2
Q
What are cells?
A
Basic functional and structural unit in a living organism.
3
Q
What are tissues? Give an example of a tissue in the circulatory system.
A
A group of cells of similar structure working together to perform a specific function. (Muscle, connective, nerve or epithelial)
4
Q
What are organs? Give an example of an organ in the circulatory system.
A
Made from a group of different tissues working together to perform a particular function. (Heart, veins or arteries.)
5
Q
What is an organ system? What is an example of an organ system?
A
Made from a group of organs with related functions, working together to perform body functions within the organism. (circulatory system, shoot system or respiratorily system)
6
Q
What is a nucleus and what is its function?
A
- Contains genetic material in chromosomes that control how cells grow and work
- controls cell division
7
Q
What is the cytoplasm and what is its function?
A
- supports cell structures
- site of many chemical reactions
- contains water and many solutes
8
Q
What is the cell membrane and what is its function?
A
- holds the cell together
- controls substances entering and leaving the cell
9
Q
What is the cell wall and what is its function?
A
- gives the cell extra support and defines its shape
10
Q
What is the chloroplasts and their function of it?
A
- site of photosynthesis, providing food for plants
- the chlorophyll pigments absorb light energy needed for the reaction to occur.
11
Q
What is the function of the vacuole?
A
- contains cell sap (storage for minerals)
- used for storage of certain material
- also helps support the shape of the cell
12
Q
What is the function of the mitochondria?
A
- site of aerobic respiration, providing energy for the cell
- cells with high rates of metabolism (carrying out many different cell reactions) will have significantly higher numbers of mitochondria than cells with lower numbers of reactions taking place in them.
13
Q
What is the function of ribosomes?
A
- It is the site of protein production in protein synthesis
14
Q
What is the function of vesicles?
A
Used to safely transport substances from one part of the cell to another.
15
Q
What are some similarities in animal and plant cells?
A
Multicellular organism Nucleus Mitochondria Cytoplasm Cell membrane
16
Q
What are some differences between plant and animal cells?
A
Fixed shape ] No fixed shape
Large vacuole } Little or no vacuole
Cell wall } No cell wall
Stores carbohydrates as Starch } Stores carbohydrates as Glycogen
Contains Chloroplasts to conduct photosynthesis } Does not contain Chloroplasts (cannot conduct photosynthesis)
16
Q
What are some differences between plant and plant cells?
A
Fixed shape ] No fixed shape
Large vacuole } Little or no vacuole
Cell wall } No cell wall
Stores carbohydrates as Starch } Stores carbohydrates as Glycogen
Contains Chloroplasts to conduct photosynthesis } Does not contain Chloroplasts (cannot conduct photosynthesis)
17
Q
What are the chemical elements present in carbohydrates?
A
Carbon, oxygen and hydrogen.
18
Q
What are the chemical elements present in protein?
A
All contain carbon, oxygen, hydrogen, and nitrogen.
come contain small amounts of other elements like sulphur
19
Q
What are the chemical elements present in lipids (fats)?
A
Carbon, oxygen, and hydorgen.
20
Q
Describe the structure of Carbohydratesas Large Molecules made up from Smaller Basic Unit?
A
starch and glycogen composed of simple sugars
21
Q
Describe the structure of the protein as Large Molecules made up from Smaller Basic unit?
A
Composed of amino acids
22
Q
Describe the structure of the lipids (fats) as Large Molecules made up from Smaller Basic unit?
A
Composed of fatty acids and glycerol
23
Q
Before carrying out the practical food tests how do you have to prepare the food?
A
- Break up the food using a pestle and mortar
- Transfer to a test tube and add distilled water
- Mix the food with the water by stirring with a glass rod
- Filter the mixture using a funnel and filter paper, collecting the solution
- Proceed with the food tests
24
How do you test for glucose?
- Add Benedict's solution to the sample solution in a test tube
- Heat in a boiling water bath for 5 minutes
- Take the test tube out of the water bath and observe the colour
- A positive test will show a colour change from blue to orange / brick red
25
How do you test for starch?
- We can use iodine to test for the presence or absence of starch in a food sample
- Add drops of iodine solution to the food sample
- A positive test will show a colour change from orange-brown to blue-black
26
How do you test for protein?
- Add drops of Biuret solution to the food sample
| - A positive test will show a colour change from blue to violet / purple
27
How do you test for lipids?
- Mix the food sample with 4cm3 of ethanol and shake
- Allow time for the sample to dissolve in the ethanol
- Strain the ethanol solution into another test tube
- Add the ethanol solution to an equal volume of cold distilled water (4cm3)
- A positive test will show a cloudy emulsion forming
28
What is CORMS?
Continuous Operational Real-Time Monitoring System
29
What are enzymes?
Protein molecule that acts as a biological catalyst by speeding up the rate of specific reaction without being used up or affected
30
What is the the role of Enzymes as Biological Catalyst in Metabolic Reactions?
Enzymes are biological catalyst in metabolic reactions (digestion) as they allow substrates to bind onto their active site, breaking them down into products
31
What enzyme turns Starch → Glucose?
Amylase/ maltase
32
What enzyme turns Protein → Amino Acids?
Protease
33
What enzyme turns Lipids → Fatty Acids & Glycerol?
Lipase
34
how does the temperature of the enzyme getting closer to the optimum affect its function?
- As the temperature increases towards optimum, the rate of enzyme activity increases
- This is because as temperature increases, enzymes and substrates will gain kinetic energy, vibrating and moving faster
- This allows more frequent successful enzyme-substrate collisions to occur, increasing the rate in which substrates are broken down, hence increasing enzyme activity
35
What happens to the function of the enzyme if the temperature goes above optimum?
- enzymes will denature
- This is because high temperatures causes bonds to vibrate more, increasing chance of bonds within enzyme breaking
- When bonds in enzymes break, shape and structure of active site will change, diminishing the ability of substrate to bind to active site of enzyme
- Therefore, enzymes denature and metabolic reactions cannot take place
36
how does the pH of the enzyme getting closer to the optimum affect its function?
- As the pH increases towards optimum, the rate of enzyme activity increases
- This is because as pH increases, the shape and structure of the active site, and the charge of substrate molecule will both be optimal to allow the substrate to bind to the active site of enzyme
- This allows more frequent successful enzyme-substrate collisions to occur, increasing the rate in which substrates are broken down, hence increasing enzyme activity
37
What happens to the function of the enzyme if the pH goes above optimum?
- However, as pH exceeds optimum, enzymes will denature
- This is because the increase/decrease from optimum pH causes the shape and structure of active site to change, additionally changing the charge fo substrates, therefore diminishing the ability of substrate to bind to active site of enzymes
- Therefore, enzymes denature and metabolic reactions cannot take place
38
What is diffusion?
Passive net movement of particles down the concentration gradient (from region of high concentration to region of low concentration) until equilibrium
39
What is osmosis?
Passive net movement of Water molecules down the Water potential gradient (from region of lower solute concentration to region of higher solute concentration) across a partially permeable membrane
40
What is active transport?
Movement of substances against the concentration gradient (from region of low concentration to region of high concentration) using energy (commonly in the form of ATP)
41
Name 4 Factors that Affect the Rate of Movement of Substances Into and Out of Cells:
Surface Area to Volume Ratio, Distance, Temperature and Concentration Gradient
42
How does the surface area to volume ratio affect the rate of movement of substances into and out of cells?
- As the surface area to volume ratio (SA:V) increases, the rate of movement of substances into and out of cells will increase
- This is because there is a larger surface area in which substances can move through, hence increasing the rate of movement of substance
43
How does the temperature affect the rate of movement of substances into and out of cells?
- As temperature increases, the rate of movement of substances into and out of cells will increase
- This is because particles gain more kinetic energy and so will move faster, hence increasing the rate of movement of substance
44
How does the concentration gradient affect the rate of movement of substances into and out of cells?
- As concentration gradient increases, the rate of movement of substances into and out of cells will increase
- This is because a stronger concentration gradient is present, hence increasing the rate of movement of substance
45
How does the concentration gradient affect the rate of movement of substances into and out of cells?
- As concentration gradient increases, the rate of movement of substances into and out of cells will increase
- This is because a stronger concentration gradient is present, hence increasing the rate of movement of substance
46
What is photosynthesis?
Production of Carbon compounds (Glucose) in cells using light energy from the Sun.
47
What is the process of photosynthesis and its importance in the conversion of light energy to chemical energy?
- Light energy from the sun is absorbed by Chlorophyll to produce Glucose which is stored as Starch for growth, and Oxygen as a waste product
- Glucose produced in Photosynthesis is passed down the food chain from one organism to another, hence why Plants are called Producers (bottom of the food chain)
- While Photosynthesis only occurs under the presence of sunlight, aerobic respiration occurs at all times of day and uses Glucose produced from Photosynthesis to produce energy (used for cell growth) and Carbon Dioxide (waste product or used for Photosynthesis)
48
What is the word equation for photosynthesis?
Carbon Dioxide + Water → Glucose + Oxygen
49
What is the balanced equation for photosynthesis?
6CO2 + 6H2O --> C6H12O6 + 6O2
50
How does varying carbon dioxide concentration affect the rate of photosynthesis?
- As the concentration of Carbon Dioxide increases, the rate of Photosynthesis will increase
- As Carbon Dioxide is a reactant in Photosynthesis, the increase in Carbon Dioxide concentration will allow more Photosynthesis to occur, hence increasing the rate of Photosynthesis
- However, as concentration of Carbon Dioxide increases beyond a certain point, rate of Photosynthesis with plateau as another factor will be the limiting factor
51
How does varying temperature affect the rate of photosynthesis?
- As temperature increases towards optimum, the rate of Photosynthesis will increase
- This is because the increase in temperature towards optimum will allow optimum enzyme activity for Photosynthesis-related enzymes, hence increasing the rate of photosynthesis
- However, as temperature increases above optimum, enzymes involved in Photosynthesis will denature, therefore causing the rate of Photosynthesis to decrease
52
How does varying light intensity affect the rate of photosynthesis?
- As light intensity increases, the rate of Photosynthesis will increase
- As Photosynthesis can only occur under the presence of light, the increase in light intensity will therefore allow more Photosynthesis to occur, increasing the rate of Photosynthesis
- However, as light intensity increases beyond a certain point, the rate of Photosynthesis will plateau as another factor is the limiting factor
53
What is the waxy cuticle?
Outermost protective layer that prevents water loss via evaporation
54
What is the upper epidermis?
Thin and transparent layer of cells to allow light to enter Palisade Mesophyll
55
what is the palisade mesophyll?
Layer tightly packed with Chloroplasts to maximize light absorption for Photosynthesis
56
What is the spongy mesophyll?
Layer containing internal air spaces to increases surface area to volume ratio for the diffusion of gases (mainly Carbon Dioxide)
57
What is the lower epidermis?
Layer containing:
- Guard cells: cells that flank and control the opening and closing of Stomata by absorbing and losing Water to regulate gas exchange and prevent water loss (via transpiration)
- Stomata: mouth-shaped opening flanked and controlled by Guard cells to regulate gas exchange and prevent Water loss (via transpiration)
58
Name 5 ways the leaf has adapted to photosynthesis?
- Large surface area
- Thin (short diffusion path)
- chlorophyll
- the network of the veins
- has stomata
59
How does a larger surface area affect the rate of photosynthesis?
Increases surface area to volume ratio (SA:V) for diffusion of Carbon Dioxide and absorption of light for Photosynthesis
60
How does the leaf being thin affect the rate of photosynthesis?
Short diffusion length which increases the rate of diffusion of Carbon Dioxide into leaf cells, e.g Chloroplasts
61
How does more chlorophyll affect the rate of photosynthesis?
Tightly packed and present in large amounts in Palisade Mesophyll to maximise light absorption for Photosynthesis
62
How does the network in veins increase the rate of photosynthesis?
Supports the leaf and transports Water for Photosynthesis and Transpiration (via Xylem), and Carbohydrates produced by Photosynthesis (via Phloem) from sources to sinks
63
How do stomata in the leaf increase the rate of photosynthesis?
Regulates gas exchange by allowing Carbon Dioxide to diffuse into the leaf for use in Photosynthesis, and Oxygen to diffuse out as waste product of Photosynthesis
64
Why do plants require minerals?
To grow
65
Name two mineral ions:
- magnesium
| - nitrate
66
What are magnesium ions needed for in plants and what is the deficiency?
Needed for: to build chlorophyll for growth
| Deficiency: Leaves turn yellow
67
What are nitrate ions needed for in plants and what is the deficiency?
needed for: to produce Amino acids to build Protein and DNA
| Deficiency: Leaves turn yellow and stunted growth
68
What is a balanced diet and why is it important for humans?
Diet in which all components needed to maintain health are present in appropriate proportions
Humans need to eat a balanced diet to ensure the body is provided with components to maintain good health
69
What does a balanced diet need to include proportions of?
```
Carbohydrates
Lipids
Water
Protein
dietary fibre
vitamins
minerals
```
70
name 3 ways the energy requirement can vary?
- age
- activity levels
- pregnancy
71
How does age affect the energy requirements?
Amount of energy required increases towards adulthood for growth and muscle development
72
How do activity levels affect the energy requirements?
The amount of energy required increases with activity level as more energy is needed to allow muscle contractions to facilitate exercise via respiration
73
What is the function of carbohydrates the deficiency and source?
Function: Direct energy source
Deficiency: Lack of energy
Source: Meat, Starch
74
What is the function of protein the deficiency and source?
function: Growth and repair
Deficiency: Marasmus - poor growth
Source: Meat
75
What is the function of vitamin A the deficiency and source?
Function: Healthy eyesight
Deficiency: Night Blindness
Source: Carrots
76
What is the function of vitamin C the deficiency and source?
Function: Heal wounds and rebuilds tissue
Deficiency: Scurvy - bleeding gums
Source: Lemon
77
What is the function of vitamin D the deficiency and source?
Function: Strengthen teeth and bones
Deficiency: Rickets - curvature of bones
Source: Margarine
78
What is the function of lipids the deficiency and source?
Function: Insulation and Energy Storage
Deficiency: none
Source: Meat
79
What is the function of Dietary fibre the deficiency and source?
Function: Lowers Cholesterol
Deficiency: Constipation
Source: Vegetables
80
What is the function of Calcium the deficiency and source?
Function: Strengthen Teeth and Bones
Deficiency: Rickets - curvature of bones
Source: Milk
81
What is the function of iron the deficiency and source?
Function: Promote Haemoglobin
Deficiency: Anaemia - poor Oxygen transport
Source: Meat
82
What is the function of water the source?
Function: Allows chemical reactions to occur
Source: Water
83
What are 6 things in the structure of the human alimentary canal?
- mouth
- oesophagus
- stomach
- small intestine (duodenum and ileum)
- large intestine (colon and rectum)
- pancreas
84
What is the function of the mouth in the alimentary canal?
- Mechanical digestion occurs
- Large food is turned into a bolus to provide large surface area to volume ratio for salivary Amylase to break down Starch in food into Glucose
- Saliva lubricates bolus for easy swallow
85
What is the function of the oesophagus in the alimentary canal?
- Tube connecting Mouth to Stomach
| - Peristalsis (wave-like contractions) occurs to push bolus down the tube towards Stomach
86
What is the function of the stomach in the alimentary canal?
- Peristalsis continues mechanical digestion, and enzymes begin chemical digestion
- Hydrochloric acid maintains Optimum pH to increase rate of enzyme activity and metabolic reactions
87
What is the function of the small intestine in the alimentary canal?
- Lined with Villi to absorb digested soluble molecules into the circulatory system for use
88
What is the function of the large intestine in the alimentary canal?
- Absorbs Water from undigested food to produce faeces (stored in the Rectum and removed through the Anus)
89
What is the function of the pancreas in the alimentary canal?
- Synthesises pancreatic enzymes (Amylase, Protease, and Lipase)
- Secretes pancreatic enzymes into the Stomach and Small intestine for digestion
90
What is the peristalsis?
Wave-like muscle contractions that push food bolus down the Oesophagus from Mouth to Anus - occurs in Stomach and Gut
91
How is food moved through the gut by the peristalsis?
- Peristalsis occurs as a result of the rhythmic contraction and relaxation of two muscles controlled unconsciously by the nervous system
- Circular muscle changes the radius of the Oesophagus, while the Longitudinal muscle changes length of Oesophagus
- Contraction of Circular muscle behind the food bolus constricts the gut to prevent bolus from being pushed back towards the Mouth
- Contraction of Longitudinal muscle where food bolus is located moves it along the gut
- As a result, wave-like muscle contractions occur which pushes the food bolus from Mouth to Anus
92
Why is food moved through the gut by the peristalsis?
- As food bolus is pushed only a few centimetres at a time, progression through intestine is slow, allowing time for digestion
- This allows the churning of semi-digested food as they mix food bolus with enzymes, increasing rate of digestion
93
What is the role of digestive enzymes?
The purpose of digestion is to break down large, insoluble molecules into smaller, soluble molecules that can be absorbed into the bloodstream. Digestion mainly takes place chemically, where bonds holding the large molecules together are broken to make smaller and smaller molecules chemical digestion is controlled by enzymes which are produced in different areas of the digestive system
94
What are the three main types of digestive enzymes?
carbohydrates, proteases and lipases
95
What breaks starch --> glucose?
Amylase/maltase
96
What breaks protein --> amino acids?
Protease
97
What breaks lipids --> fatty acids and glycerol?
Lipase
98
Where is bile produced and where is it stored?
produced in the liver and stored in the gall bladder
99
What is bile?
Alkaline substance produced in the Liver and stored in the Gall Bladder
100
What does bile do?
Bile emulsifies large Lipid molecules into droplets with larger surface area to volume ratio to increase the rate of digestion
101
What are the functions of bile?
- neutralising stomach acid
| - emulsifying lipids
102
How does bile neutralize stomach acid?
Enzymes in Small intestine function optimally in Alkaline conditions (optimum pH of 8-14)
However, churning of food in Stomach by Hydrochloric acid creates Acidic environment
Therefore, Bile will neutralise Hydrochloric acid to maintain Alkaline conditions, allowing optimum enzyme activity and increasing the rate of metabolic reactions
103
How does bile emulsify lipids?
As the breakdown and digestion of Lipid molecules require a long period of time, Bile is used to emulsify large Lipid molecules into small droplets
Lipid droplets will have a larger surface area to volume ratio, allowing faster breakdown by Lipase into Fatty acids and Glycerol, hence increasing the rate of lipid digestion
104
What is villus?
Small finger-like projections lining the Intestine wall that absorb digested soluble food molecules
105
How has the small intestine adapted for absorption?
- thin cell wall
- large surface area to volume ratio
- dense capillary network
- lacteal
106
Benefits of a thin cell wall in the small intestine?
Thin cell wall (one cell thick) to minimise distance of diffusion of digested soluble molecules, therefore increasing the rate of absorption
107
What is the benefit of a large surface area to volume ratio in the small intestine?
Folded to increase surface area to volume ratio for diffusion of digested soluble molecules, therefore increasing the rate of absorption
108
What is the benefit of a dense capillary network in the small intestine?
Dense capillary network nearby to provide rich blood supply, creating a strong concentration gradient for the diffusion of digested soluble molecules, therefore increasing the rate of absorption
109
What is the benefit of lacteal in the small intestine?
Lacteal absorbs and transports Fatty acids and Glycerol from Intestine to Lymphatic system
110
What class of enzyme is amylase, what is the source? What does it break down and produce?
Class: carbohydrates
source: Salivary gland/pancreas
breaks down: Starch
produces: Maltose
111
What class of enzyme is maltase, what is the source? What does it break down and produce?
Class: carbohydrates
source: Small intestine wall
breaks down: maltose
produces: glucose
112
What class of enzyme is pepsin, what is the source? What does it break down and produce?
Class: protease
source: stomach
breaks down: protien
produces: amino acids
113
What class of enzyme is trypsin, what is the source? What does it break down and produce?
Class: protein
source: pancreas
breaks down: protein
produces: amino acids
114
What class of enzyme are lipases, and what is the source? What does it break down and produce?
Class: lipases
source: pancreas
breaks down: lipids
produces: fatty acids and glycerol
