Lower Remove Topics Flashcards
What are the living characteristics?
M ovement
R espiration
S ensitivity
C ontrol of internal conditions
G rowth
R eproduction
E xcretion
N utrition
What is a eukaryote/eukaryotic organism?
Any organism whose cell has a clearly defined nucleus.
What are common features of:
Plants
Animals
Fungi
Protoctists
Plants - Multicellular, cells contain chloroplasts. They can carry out photosynthesis and have cellulose cell walls. Store carbohydrates as starch or sucrose.
Animals - Multicellular, do not contain chloroplasts. They can’t carry out photosynthesis and have no cell walls. Usually have nervous co-ordination and can move from one place to another; often store carbohydrate as glycogen.
Fungi - Can’t carry out photosynthesis; body is usually organised into a mycelium, made from thread-like structures called hyphae, which contain many nuclei. Some are single-celled, with cell walls made of chitin. May store carbohydrates as glycogen.
Protoctists - Microscopic single-celled organisms. Some live in pond water and will have features like an animal cell, while others have chloroplasts and are more like plants. Some are pathogens as well.
What are some common features of bacteria?
Bacteria - Microscopic single-celled organisms, they have a cell wall, cell membrane, cytoplasm and plasmids. They lack a nucleus but contain a circular chromosome of DNA. Some can carry out photosynthesis but most feed off of other living or dead organisms.
Can be helpful (e.g. Lactobacillus Bulgaricus, used in yoghurt production) and some can be harmful (e.g. Cholera).
What are some common features of viruses?
Viruses - Not living organisms. Small particles, smaller than bacteria. Can only reproduce inside living cells. They infect every type of living organism, and have a wide variety of shapes and structures. Have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA.
What is a pathogen, and what groups may it include?
A pathogen can be a fungus, bacterium, protoctist or a virus. it is a disease causing microorganism.
What are the levels of organisation in organisms? (Smallest to largest)
Organelle, Cell, Tissue, Organ, Organ system, Organism.
What is the structure of the:
Nucleus
Cytoplasm
Cell Membrane
Cell wall
Mitochondria
Chloroplasts
Ribosomes
Vacuole
Nucleus - A cell’s genetic material (DNA) enclosed by a double membrane - the nuclear envelope
Cytoplasm - Gel-like substance. Contains nutrients, salts and organelles dissolved in it.
Cell Membrane - Selectively permeable barriers, made of proteins
Cell wall - A barrier providing protection and structural support. Made of cellulose in plants.
Mitochondria - Organelles, contain enzymes
Chloroplasts - Enclosed by a double membrane envelope.
Ribosomes - Tiny structures, made of RNA and Protein
Vacuole - Large, fluid filled sac surrounded by a membrane
What is the function of the:
Nucleus
Cytoplasm
Cell Membrane
Cell wall
Mitochondria
Chloroplasts
Ribosomes
Vacuole
Nucleus - To house the genetic material (DNA) and regulate cellular activity
Cytoplasm - To hold the internal components of cells in place and protect them from damage
Cell Membrane - To provide protection for the cell, and regulate the movement of substances in and out of the cell
Cell wall - To provide strength and structure to the cell
Mitochondria - To generate energy to power the cell’s biochemical reactions
Chloroplasts - To carry out photosynthesis
Ribosomes - To carry out protein synthesis to form proteins
Vacuole - To store water, nutrients and waste
What are the similarities and differences between animal and plant cells?
SIMILARITY
Cell membrane
Cytoplasm
Nucleus
Mitochondria
Ribosomes
DIFFERENCE
Cell wall
Chloroplasts
Vacuole
Why is cell differentiation important?
It enables the body to perform specific functions and be more suited to its environment.
What are the advantages and disadvantages of using stem cells in medicine?
Advantages:
Organs/Tissues can be repaired
Untreatable conditions can be treated
Can grow organs for transplant
Less need for organ donor matching
Disadvantages:
The body may reject the cells
Immunosuppressive drugs are used, which can increase the risk of other illnesses
Long-term effects are still not known
What are:
Carbohydrates
Proteins
Lipids (fats and oils)
Large molecules of (what are they made up of)?
Carbohydrates - Sugar/Glycogen/Glucose
Proteins - Amino acids
Lipids (fats and oils) - Glycerol and fatty acids
How would you investigate a food for the presence of glucose?
You would use Benedict’s solution. It will turn brick red if present, and stay blue if glucose is not present.
How would you investigate a food for the presence of starch?
You would add iodine solution. It will turn blue/black in the presence of starch, and stay yellow/brown if no starch is present.
How would you investigate a food for the presence of protein?
You would add Biuret solution. It will turn purple in the presence of protein, and blue if negative.
How would you investigate a food for the presence of fat?
You would add ethanol and then water. It will turn to a cloudy white emulsion in the presence of lipids.
What is the role of enzymes in a reaction?
Enzymes are biological catalysts, and they release energy, speeding up the reaction.
How does temperature change affect enzyme function?
As temperature increases, enzymes work better, until they get to a point where it is too hot and the enzymes start to denature. This is because high temperatures disrupt the shape of the active site, which will reduce its activity, or prevent it from working.
Why is enzyme function affected by changes in pH?
Active sites often have residues with acidic and basic properties that are important for catalysts. Changes in pH can affect these and make it harder for substrate complexes to form.
What are diffusion, osmosis and active transport?
Diffusion - The net movement of molecules along the concentration gradient.
Osmosis - The net movement of water molecules along the concentration through a semi-permeable membrane.
Active Transport - The net movement of molecules against the concentration gradient
What effect does surface-area to volume ratio have on the rate of movement of substances?
A higher surface-area volume ratio means the rate of movement will be higher, as there is more surface area to move through (more at one time)
A lower surface-area volume ratio means the rate of movement of substances will be lower, because there is less surface area to move through.
What is photosynthesis? Why is it important?
Photosynthesis is the process of converting light energy, CO2 and water into glucose and O2. It is important because it provides plants with energy to grow, respire, etc…
What is the word equation and balanced symbol equation for photosynthesis?
Water + Carbon Dioxide (sunlight) —-> Oxygen + Glucose
6H₂O + 6CO₂ (sunlight) –> 6O₂ + C₆H₁₂O₆
What is the structure of a leaf? (Label the diagram)
How are the:
Waxy cuticle
Upper Epidermis
Palisade layer/mesophyll
Spongy Mesophyll
Vascular bundle
Lower Epidermis
Guard cells
adapted for photosynthesis?
Waxy cuticle - Transparent and impermeable to allow sunlight through, but not allow infection/pathogens in and not allow water vapour to be lost.
Upper Epidermis - Transparent to allow light to enter the leaf.
Palisade layer - Packed with chloroplasts to maximise photosynthesis.
Spongy mesophyll - Lots of air gaps to allow for diffusion and gas exchange.
Vascular bundle - Contains Phloem and Xylem to provide the leaf with water and take glucose to other parts of the plant
Lower Epidermis - Contains stomata to allow for gas exchange.
Guard cells - Close and open the stomata to minimise water loss at night when photosynthesis can’t take place (as light is a limiting factor).
What mineral ions are needed for growth in plants? What are the signs of deficiencies of these ions?
Magnesium - Needed for chlorophyll. If the plants leaves are yellow/red, especially between leaf veins, the plant lacks magnesium ions.
Nitrates - Needed for amino acids (proteins). If the leaves are yellow or pale, it is a sign of nitrate deficiency.
What 7 things should a balanced diet in humans include?
Carbohydrates, proteins, lipids, vitamins, minerals, water and fibre.
What are the uses and sources of:
Carbohydrates
Proteins
Lipids (Fats and oils)
Vitamins A, C and D
Calcium and iron ions
Water
(Dietary) fibre
in humans?
Carbohydrates: Slow-release energy, found in grains, fruits, vegetables, e.g. bread, pasta, peas.
Proteins: Building and repairing tissues, found in meat, fish, eggs and dairy, e.g. chicken, salmon
Lipids: Energy storage, hormone regulation, found in oils, fatty foods, meat, seeds, e.g. Nuts, avocado
Vitamins A, C and D: A - Vision and immune function, found in eggs, orange fruits
C - Antioxidants, found in broccoli, bell peppers
D - Bone health and calcium absorption, found in fish, egg yolks
Calcium and iron ions:
Calcium - Bone/teeth health, muscle function, found in dairy e.g. milk, yoghurt
Iron - Oxygen transport, immune functions, found in shellfish, red meat, e.g. oysters, beef
Water: Regulates body temp, found in water and drinks, and fruits
Fibre: Digestive health, reduces risk of type 2 diabetes and chronic diseases, found in fruits, vegetables, nuts.
Label the diagram. What is the function of each label?
Mouth - To ingest food
Salivary gland - To produce saliva to water down food
Esophagus - To carry food to the stomach to be digested
Stomach - To digest food
Liver - To produce bile for digestion
Gallbladder - To store and concentrate bile
Pancreas - To produce enzymes and insulin + glucagon
Large intestine - Absorbs water and electrolytes from food
Small intestine - Absorbs nutrients and water from digested food
Rectum/Anus - To excrete/remove waste from the body
How is the food moved through the gut?
Peristalsis is the contraction of muscles to push food down the digestive system.
What enzyme(s) digest(s) starch? What is it digested into?
Amylase and Maltase digest starch into glucose.
What enzyme(s) digest(s) proteins? What is it digested into?
Protease digests protein into amino acids.
What enzyme(s) digest(s) lipids? What is it digested into?
Lipase digests lipids into fatty acids and glycerol.
Where is bile produced and stored?
Bile is produced in the liver and stored in the gall bladder.
What does bile do?
It neutralises stomach acids and emulsifies lipids.
How is the small intestine adapted for absorption?
It has lots of villi, which are little spikes that increase the surface area of the small intestine, which means it can absorb more water and nutrients.
What does respiration produce in organisms?
What does this provide for cells?
Respiration produces ATP, which provides energy for cells (ATP is a type of energy)
What are the differences between aerobic and anaerobic respiration?
Oxygen vs No oxygen
CO2, H2O vs Lactic Acid
Slow, but more vs fast but less
Product completely oxidised vs product incompletely oxidised
What is the word equation and balanced symbol equation for anaerobic respiration?
Glucose + Oxygen –> Lactic Acid + Carbon Dioxide
C₆H₁₂O₆ + 6O₂–> 6CO₂ + 6H₂O (+ energy released + Lactic acid)
What is the word equation for anaerobic respiration (IN PLANTS ONLY)?
Glucose –> Ethanol + Carbon Dioxide + Energy
What is the structure of the lungs
(The alveoli are at the end of the bronchioles)
What is the role of the intercostal muscles in ventilation/respiration?
When you inhale, the external intercostal muscles pull together to expand your rib cage. This increases the volume and decreases air pressure inside the lungs, which creates suction to pull air in. They then relax in exhalation, causing the ribcage to move downwards and inwards, reducing the volume and increasing air pressure, which forces air out of the lungs.
What is the role of the diaphragm in ventilation/respiration?
The diaphragm contracts and flattens, and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. Upon exhalation, the diaphragm relaxes and returns to its domelike shape, and air is forced out of the lungs
Why is smoking bad for the lungs and circulatory system?
It can damage the alveoli, which stops gas exchange. It can also block the pulmonary vein/artery, which stops circulation.
