SMDDDDD Flashcards
what does the xylem do
it transports water and mineral ions from the root upwards to the leaves
what do lignin walls do
strengthens xylem
what do phloem transport
sugars from the leaves to area of storage
what do palisade cells contain
lots of chloroplasts which absorb light in photosynthesis and make sugar/glucose. palisade cells are densely packed to maximise absorption of light
How to calc Magnification
image over actual and to convert nm to mm times 1000
Define diffusion
Net movement of particles from an area of high concentration to low concentration
How do substances enter cells
By diffusion through cell membrane
How can diffusion speed be increased in some organism
- Reduced diffusion distances, shorter distance equals to faster diffusion
- Concentration gradient kept high, equilibrium is not reached so diffusion continues
- Large surface area for diffusion to tak3 place across the cell membranes
Osmosis
Net movement of water molecules from an area of high water potential to an area of low water potential across a partially permeable membrane
How does water enter cells
Osmosis
How does osmosis affect plant and animals differently
Plant cells not permanently damaged , cell walls give plants cell support
Animal cells permanently damaged and cells shrink with water loss and wil burst if swelled too much
Define active transport
Net movement of particles from area of low concentration to high concentration as it requires energyyyy
What are the two groups of carbs called
Monosaccharides and polysaccharides
What are proteins
Chains of amino acids who order has been determined by genes
What is the structure of a lipid
3 fatty acids and 1 glycerol molecule
What is theFood test for starch
Iodine,
Positive result means it turns blueish black
Name the complementary bases
Adenine and thymine, Guanine and cytosine (ATGC)
What is the rate of enzyme activity at low temp
Enzymes and substrates hv little kinetic energy so they don’t collide quickly, hence the rate of reaction is low
What happens to enzymes at very high temp
It becomes denatured as the active site changes shape meaning that the substrate can no longer fit
Give me the photosynthesis equation
Carbon dioxide + water => glucose + oxygen
Function of chlorophyll
Transfers light energy to chemical energy
Energy produced used for synthesis of carbohydrates
Limiting factors for photosynthesis
Temperature, carbon dioxide, light intensity
In leafs, how is the waxy cuticle adapted for its function
It prevents transpiration ( loss of water vapour)
how is the upper epidermis adapted to its function
Transparent to allow light to enter leaf
How is the palisade mesophyll adapted for its function
Contains lots of chloroplasts which absorb light in photosynthesis
How is the spongy mesophyll adapted to its function
Air spaces to allow gases to diffuse
In the vein, containing xylem and phloem, what do they do
Xylem brings water to the leaf and phloem removes sugar
How are the guard cells adapted to its function
Controls opening and closing of stomata
How is the stomata adapted to its function
Allow carbon dioxide into the leaf and oxygen out
Where is the enzyme amylase made in
Salivary glands, small intestine and pancreas
What does amylase do hint break down
Breaks down starch into Maltose, and is secreted into alimentary canal
what does Maltase do
Breaks down maltose into glucose which gets secreted onto membranes of epithelium in small intestine
What does protease do and where is in located in the body
Digests proteins into amino acids, it is made in stomach small intestine and pancreas
Where is pepsin found in
Stomach
Where is trypsin found in
Smal intestine
What does lipase do
Breaks down lipids into fatty acids and glycerol
Where is lipase made in
Small intestine and pancreas
Describe the process of peristalsis
The muscular contractions of the oesophagus wall forms the bolus from the food passing down, which pushes it down the oesophagus into stomach
What does the stomach do
Churns the food and destroys the pathogens
What is bile and what is its function
Bile is made in the liver, stored in the gallbladder and released into the small intestine. It’s function is that it emulsifies and breaks down large fat droplets into small ones, increase the surface area
How is the small intestine adapted for its function
Large surface area provided by villi and micro villi, lots of capillaries, thin wall so theres short diffusion distance and lacteal to help with absorption of fat
Define assimilation
Movement of difgested food into cells where they are used
Describe the movement of bloood around the body starting at the right atrium
Deoxygenated blood enters the right atrium via the vena cava
Right atrium contracts forcing blood through tricuspid valve into the right ventricle
Blood enters the right ventricle and leaves via the pulmonary artery
Blood flows to the lungs
Blood becomes oxygenated
Blood returns to the heart and enters the left atrium via the pulmonary vein
Left atrium contracts blood forcing blood into the aorta
Oxygenated blood flows around the body and is used in respiration
Why are the walls of ventricles of the heart thicker than the atria
They pump blood further and at higher pressure
Why are the walls of the left ventricle thicker than the right
They are thicker because they pump blood further and and higher pressure
What is the term double circulatory system called double circulatory system
The blood pumps into the heart twice for every once it passes around the rest of the body
Factors increasing chances of getting coronary heart disease
Sendentary lifestyle, high fat diet, smoking, stress, heriditary
Explain why reducing blood supply to the heart muscles cells can cause a heart attack
Less oxygen, less aerobic respiration, lactic acid and low pH
How can heart activity be monitored
By using a ECG pulse rate and listening to valves with stethoscope
How is energy lost from food chain
Energy is lost by cellular respiration in the primary consumer
Energy is used in body movement of consumer
Energy is lost in the undigested food that is not absorbed into the consumer and is egested from the body as faeces
Energy is lost in the uneaten parts of the primary consumer some parts could be inaccessible to the consumer
Outline the production of carbohydrates in photosynthesis
Light is absorbed by chrolopyhll, light energy is converted to chemical energy, some of the energy is used for production of atp, water molecules are split or photolysed, it produces oxygen as waste product and plants absorb co2 from air or water, atp is needed, and excess glucose is converted to starch
Explain how ventilation maintain gas exchange
Ventilation brings air with high oxygen concentration into the lungs, ventilation due to muscle contractions causes pressure changes in the thorax. The contraction of external intercostal muscles and diaphragm occurs during inspiration
Factors affecting population growth
Food supply, predation, diseases,
How does dna code for protein
Each dna nucleotide codes for an rna nucleotide, these nucleotides code for one amino acid. The sequence of bases in a gene is code for sequence of amino acids in a protein
How does dna control cell function
Controls production of protein, protein include enzymes and antibodies, receptors for neurotransmitters
Insulin secreted by pancreas:
Converted glucose to glycogen
How are the alveoli adapted for gas exchange
There is a large number of alveoli to increase surface area, the lining is moist for rapid diffusion, there is a good blood supply and it’s walls are thin to enable short diffusion pathway
Explain how smoking can increase the risk of a disease called emphysema
Chemicals in cigarette smoke causes white blood cells to secrete an enzyme that breaks down elastic fibres in the walls of the alveoli resulting in the reduction of surface area for gas exchange
State the gap that is between two neurons
Synaptic cleft
Explain how gas exchange is maintained in the human respiratory system
Ventilation brings air with high oxygen concentration into the lungs, ventilation due to muscle contractions causing pressure changes in the thorax, contraction of external intercostal muscles and diaphragm occurs during inspiration, the alveoli is surrounded by many capillaries, there is also large number of alveoli for increased surface area, and concentration gradient of oxygen is maintained by ventilation, O2 and co2 diffuses .
Explain how the circulatory system is able to transport blood under high pressure from heart to rest of body
Thick muscular wall in the left ventricle
Contraction of left ventricle pumps blood at high pressure
Closure of bicuspid valve ensures no back flow of blood to the left atrium
And narrow lumen of arteries to help maintain pressure
What causes reactions in the Calvin cycycle to stop
Lack of atp and nadph
What is negative feedback in homeostasis
Reverse effect of a stimulus. It restores the normal conditions of the internal environment. When this happens, the corrective responses will be switched off.
Outline the structure of the coronary arteries
Think muscular wall, thick layer of elastic fibres, small or narrow lumen , and absence of valves
