Biology AOS 2 Flashcards

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1
Q

What are the key organ systems involved in the main homeostatic processes?

A

digestive system, respiratory system, circulatory system, excretory system, and nervous system.

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2
Q

What is the digestive system?

A

The digestive system breaks down food into nutrients for energy, growth, and cell repair, involving organs like the mouth, stomach, intestines, and liver.

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3
Q

What is the respiratory system?

A

The respiratory system facilitates gas exchange, bringing oxygen into the body and removing carbon dioxide, involving the lungs

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4
Q

What is the circulatory system?

A

The circulatory system transports blood, nutrients, oxygen, and waste products throughout the body, involving the heart, blood vessels, and blood.

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5
Q

What is the excretory system?

A

The excretory system removes waste products and excess substances from the body, involving the kidneys, bladder, and associated ducts.

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6
Q

What is the nervous system?

A

The nervous system controls and coordinates body activities by transmitting signals between different body parts, involving the brain, spinal cord, and nerves.

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7
Q

What is the function of the xylem?

A

Plant tubes that carry water and minerals from roots to the rest of the plant. Which is unidirectionally.

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8
Q

What is the function of the Phloem?

A

Plant tubes that transport sugars and nutrients from leaves to other plant parts. Which is transported bidirectionally.

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9
Q

What is transpiration? What effect does it have on plants?

A

Transpiration is the process of water movement through plants from roots to leaves, followed by its evaporation from leaf surfaces. It facilitates nutrient uptake, maintains plant structure, and regulates temperature. However, excessive transpiration can lead to water stress and wilting.

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10
Q

Describe the process of digestion including ingestion, digestion, absorption and elimination. Ensure you include all key organs.

A

Ingestion (mouth), digestion (mouth, stomach, small intestine), absorption (small intestine), elimination (large intestine, rectum, anus).

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11
Q

What is the difference between mechanical and chemical digestion and where do they occur?

A

Mechanical digestion: Breaking food into smaller pieces by chewing and squeezing it with muscles in the stomach and intestines whilst, Chemical digestion: Breaking down food into simpler parts using special chemicals called enzymes made by organs like the stomach and pancreas

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12
Q

Explain the basic structure of the nephron using the following: glomerulus, loop of Henle, Bowman’s capsule, collecting duct.

A

Glomerulus: filtration, Bowman’s capsule: collects filtrate, loop of Henle: concentrates urine, collecting duct: transports urine.

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13
Q

What is the function of the kidney? What do the kidneys produce?

A

Kidneys filter blood, regulate fluid/electrolyte balance, maintain acid-base balance; they produce urine, erythropoietin, renin.

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14
Q

What is a hormone and what kinds of tissues and organs are they produced by?

A

Hormones are chemical messengers produced by endocrine glands like pituitary, thyroid, adrenal glands, pancreas, gonads.

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15
Q

How do hormones travel around the body and communicate to target cells?

A

Hormones travel through the bloodstream and bind to specific receptors on target cells, triggering a physiological response.

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16
Q

What is homeostasis?

A

Your body maintaining a stable environment, like body temperature (optimal 36.5-37.5 degrees), pH level ( Optimal pH of blood is 7.35-7.45), blood sugar levels, fluid balance.

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17
Q

How does the Stimulus response model work?

A

the behavior that is made by a living organism which is the result of an external or internal stimulus.

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18
Q

What are the components of the stimulus response model?

A

The stimulus-response model involves a stimulus triggering a receptor, which sends a signal to a control center, leading to an effector response that restores homeostasis.

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19
Q

What is negative feedback?

A

Negative feedback is a process in which the body responds to a change by counteracting that change, maintaining stability and homeostasis.

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20
Q

Describe the stimulus-response model for when your temperature is too high

A

Increase in temperature -> thermoreceptors -> hypothalamus -> sweat glands and blood vessels -> sweating, vasodilation -> cooling down.

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21
Q

Describe the stimulus-response model for when there is decrease in temperature.

A

Decrease in temperature -> thermoreceptors -> hypothalamus -> muscles and blood vessels -> shivering, vasoconstriction -> warming up.

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22
Q

List and explain the four types of heat transfer.

A

Convection: fluid movement, Conduction: direct contact, Radiation: electromagnetic waves, Evaporation: liquid to gas.

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23
Q

Define alpha cells.

A

which is located in the pancreas, produces glucagon, which raises blood glucose level.

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24
Q

Define beta cells.

A

Beta cells are cells that make insulin, a hormone that controls the level of glucose (a type of sugar) in the blood.

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25
Q

Define Islets of Langerhans.

A

Islets of Langerhans are clusters of pancreatic cells that include alpha, beta, and other cell types involved in glucose regulation.

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26
Q

What is Glucose?

A

Glucose is a simple sugar and main energy source for cells.

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27
Q

Define glycogen.

A

Glycogen is a form of stored glucose found mainly in the liver and muscles, providing a source of energy when needed. It’s created through glycogenesis

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28
Q

Define glycogenesis.

A

Glycogenesis is where glucose molecules are linked together to form glycogen for storage in liver and muscle cells. Glycogenolysis is the breakdown of glycogen

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29
Q

Define insulin.

A

secreted (hidden) by beta cells in the pancreas when blood glucose is elevated, to lower it

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30
Q

Define glucagon.

A

secreted by alpha cells in the pancreas when blood glucose is low, to elevate it

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31
Q

Describe the homeostatic mechanisms used when blood glucose is high.

A

Stimulus Response model - High blood glucose -> beta cells -> insulin -> glucose uptake and glycogenesis -> lower blood glucose.

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32
Q

Describe the homeostatic mechanisms used when blood glucose is low.

A

Low blood glucose -> alpha cells -> glucagon -> glycogenolysis and gluconeogenesis -> higher blood glucose.

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33
Q

Define antidiuretic hormone (ADH).

A

adds aquaporins – to keep water in the body, increase water, produced by hypothalamus

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34
Q

Define nephron.

A

Functional unit of the kidney that filter blood.

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35
Q

Define kidney.

A

Kidney filters blood to remove waste, maintains electrolyte balance, and regulates blood pressure.

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36
Q

Define renin.

A

Renin is an enzyme released by kidneys that starts the process of blood pressure regulation.

37
Q

Define Aldosterone.

A

Aldosterone is a hormone that increases sodium and water reabsorption in the kidneys, raising blood pressure.

38
Q

Define aquaporin.

A

Aquaporin is a protein that forms water channels in cell membranes, facilitating water transport.

39
Q

Define filtrate

A

Filtrate is the liquid that passes through the glomerulus into Bowman’s capsule, beginning the urine formation process.

40
Q

Define osmosis.

A

water molecules which move through the semi permeable membrane which is passive. Diffusion of water molecules.

41
Q

Define baroreceptor.

A

Baroreceptor is a sensory receptor that detects changes in blood pressure and sends signals to the brain to maintain homeostasis.

42
Q

Define osmoreceptor.

A

Osmoreceptor is a sensory receptor that detects changes in osmotic pressure and helps regulate water balance.

43
Q

Describe how the body responds to low water balance.

A

Low water balance -> osmoreceptors -> hypothalamus -> ADH release -> increased water reabsorption in kidneys -> water conservation.

44
Q

What are the key differences between Type 1 and Type 2 diabetes?

A

Type 1: autoimmune destruction of beta cells, no insulin production. Type 2: insulin resistance, often associated with obesity.

45
Q

What is hyperglycemia and what impact does this condition have in both the long and short term?

A

Hyperglycemia is high blood glucose levels. Short-term: increased thirst and urination, fatigue. Long-term: damage to eyes, kidneys, nerves, and cardiovascular system.

46
Q

What is hyperthyroidism and what impact does this condition have in both the long and short term?

A

Hyperthyroidism is excessive thyroid hormone production. Short-term: increased metabolism, weight loss, anxiety. Long-term: heart problems, osteoporosis.

47
Q

What are the differences between a prokaryote and a eukaryote?

A

Prokaryotes are simple, unicellular organisms without a nucleus, with DNA residing in the cytoplasm. Examples include bacteria. In contrast, eukaryotes are complex cells with a nucleus and membrane-bound organelles. Their DNA is enclosed within the nucleus. Examples include plant and animal cells.

48
Q

What is the structure of a prokaryotic cell?

A

A prokaryotic cell includes a cell membrane, cell wall, cytoplasm, ribosomes, and DNA located in the nucleoid region. Prokaryotes lack membrane-bound organelles, making them simpler than eukaryotic cells.

49
Q

What is the structure of an animal cell?

A

An animal cell consists of a nucleus, mitochondria, rough and smooth endoplasmic reticulum (ER), Golgi apparatus, ribosomes, lysosomes, and a cell membrane.

50
Q

What is the structure of a plant cell?

A

A plant cell includes a nucleus, mitochondria, rough and smooth ER, Golgi apparatus, ribosomes, chloroplasts, cell wall, and a large central vacuole.

51
Q

What are three organelles found in an animal cell and their functions?

A

The nucleus contains genetic material and controls cell activities. Mitochondria produce energy (ATP) through cellular respiration. Lysosomes digest and recycle cellular waste, aiding in the maintenance and functionality of the cell.

52
Q

What are three organelles specific to a plant cell and their functions?

A

Chloroplasts conduct photosynthesis to produce food for the plant. The cell wall provides structure and protection, ensuring the cell maintains its shape. The large central vacuole maintains cell pressure, stores nutrients, and disposes of waste, aiding in overall cell health and function.

53
Q

What is the difference between cytosol and cytoplasm?

A

Cytosol is the fluid component of the cytoplasm, where various cellular processes occur. Cytoplasm, on the other hand, includes the cytosol as well as all the organelles except for the nucleus. It is the entire content within the cell membrane, excluding the nucleus, facilitating the movement of materials within the cell.

54
Q

What is a vacuole?

A

A vacuole is a membrane-bound organelle that stores nutrients, waste products, and helps maintain cell pressure. In plant cells, the large central vacuole also supports cell structure and growth by retaining water, thus maintaining turgor pressure against the cell wall.

55
Q

What is a vesicle?

A

A vesicle is a small, membrane-bound sac that transports substances within the cell. Vesicles are essential for the transport of proteins and lipids between different compartments of the cell, including the endoplasmic reticulum, Golgi apparatus, and the cell membrane.

56
Q

What is the Golgi apparatus and its function?

A

The Golgi apparatus is an organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles. It is critical in processing molecules synthesized in the endoplasmic reticulum and preparing them for their specific functions within or outside the cell.

57
Q

What is the nucleus and its function?

A

The nucleus is the control center of the cell, containing the genetic material (DNA) and directing all cellular activities, including growth, metabolism, and reproduction. It is surrounded by a nuclear envelope that regulates the exchange of materials between the nucleus and the cytoplasm.

58
Q

What are ribosomes and their function?

A

Ribosomes are molecular machines that synthesize proteins by translating messenger RNA (mRNA) into amino acid sequences. They can be found floating in the cytoplasm or attached to the rough endoplasmic reticulum, playing a crucial role in protein production necessary for cellular functions.

59
Q

What is the cell wall and its function?

A

The cell wall is a rigid outer layer found in plant cells, fungi, and certain prokaryotes. It provides structural support, protection, and shape to the cell. In plants, the cell wall is primarily composed of cellulose and helps maintain cell integrity against mechanical stress and osmotic pressure.

60
Q

What is a chloroplast and its function?

A

Answer: A chloroplast is an organelle found in plant cells and some protists that conducts photosynthesis. It contains chlorophyll, which captures light energy and converts it into chemical energy in the form of glucose, providing essential nutrients for the plant and oxygen as a byproduct.

61
Q

What are mitochondria and their function?

A

Mitochondria are known as the powerhouses of the cell because they produce energy (ATP) through cellular respiration. They convert glucose and oxygen into ATP, carbon dioxide, and water, supplying the energy required for various cellular processes.

62
Q

What is the difference between rough ER and smooth ER?

A

The rough endoplasmic reticulum (ER) has ribosomes attached to its surface, synthesizing proteins. The smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium ion storage. Both types of ER are essential for different aspects of cellular metabolism and production.

63
Q

What is the cytoskeleton and its function?

A

The cytoskeleton is a network of protein fibers that provides structural support, shape, and facilitates cell movement and division. It includes microfilaments, intermediate filaments, and microtubules, each playing distinct roles in maintaining cell integrity, enabling intracellular transport, and organizing the cell’s components.

64
Q

What is a plasmid?

A

A plasmid is a small, circular DNA molecule found in bacteria and some eukaryotes that is separate from chromosomal DNA. Plasmids often carry genes that provide additional functions, such as antibiotic resistance, and are used in genetic engineering to introduce new genes into organisms.

65
Q

What is the SA
ratio and why is it important?

A

The surface area to volume (SA) ratio is the proportion of a cell’s surface area to its volume. A higher SA
ratio allows for more efficient exchange of materials (nutrients, waste) between the cell and its environment, which is crucial for maintaining cellular function and health, especially in smaller cells.

66
Q

What is a phospholipid bilayer?

A

The phospholipid bilayer is a double layer of phospholipids forming the basic structure of the cell membrane. Each phospholipid molecule has a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tails, creating a semi-permeable membrane that regulates the movement of substances in and out of the cell.

67
Q

What is the structure of the plasma membrane?

A

The plasma membrane consists of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates. Proteins facilitate transport and communication, cholesterol stabilizes membrane fluidity, and carbohydrates are involved in cell recognition.

68
Q

Why is the plasma membrane described using the fluid mosaic model?

A

The fluid mosaic model describes the plasma membrane as a flexible layer with various proteins and molecules embedded within the phospholipid bilayer. This model highlights the dynamic and fluid nature of the membrane, where components can move laterally, allowing for flexibility, communication, and transport.

69
Q

What are the three types of passive transport?

A

The three types of passive transport are diffusion, osmosis, and facilitated diffusion. Diffusion is the movement of molecules from high to low concentration. Osmosis is the diffusion of water across a semipermeable membrane. Facilitated diffusion involves transport proteins helping molecules move across the membrane down their concentration gradient.

70
Q

What is the difference between active and passive transport?

A

Active transport requires energy (ATP) to move substances against their concentration gradient, from low to high concentration. In contrast, passive transport does not require energy and moves substances down their concentration gradient, from high to low concentration, through processes like diffusion and osmosis.

71
Q

What is a concentration gradient and how does it impact passive transport?

A

A concentration gradient is the difference in the concentration of a substance across a space or membrane. It drives passive transport processes, such as diffusion and osmosis, by moving molecules from areas of high concentration to areas of low concentration, facilitating the equal distribution of substances.

72
Q

What is tonicity?

A

Tonicity refers to the relative concentration of solutes in solutions.

73
Q

what the different tonicity types and how do they differ?

A

A hypertonic solution has a higher solute concentration, causing cells to lose water. A hypotonic solution has a lower solute concentration, leading cells to gain water. An isotonic solution has equal solute concentration, maintaining cell equilibrium without net water movement.

74
Q

What are the two types of active transport and how does bulk transport work?

A

The two types of active transport are primary and secondary. Primary active transport uses ATP directly to move substances, while secondary active transport uses the electrochemical gradient. Bulk transport involves moving large molecules via vesicles through endocytosis (into the cell) and exocytosis (out of the cell).

75
Q

What are protein pumps?

A

Protein pumps are transmembrane proteins that actively move ions against the gradient of concentration across membranes.

76
Q

What is the role of ATP in active transport?

A

ATP provides the energy required for active transport processes, allowing cells to move substances against their concentration gradients. This energy is used to power transport proteins that pump ions and molecules across the cell membrane, ensuring the cell maintains necessary concentrations of various substances.

77
Q

What are the stages of binary fission?

A

Binary fission involves three main stages: DNA replication, where the cell’s DNA is copied; chromosome segregation, where the duplicated chromosomes are separated; and cytokinesis, where the cell divides into two genetically identical daughter cells. This process is common in prokaryotes like bacteria.

78
Q

What are the stages of mitosis and its purpose?

A

Mitosis consists of four stages: prophase (chromosomes condense), metaphase (chromosomes align in the center), anaphase (chromosomes separate), and telophase (chromosomes decondense). The purpose of mitosis is to ensure that each daughter cell receives an identical set of chromosomes, facilitating growth and repair in multicellular organisms.

79
Q

What are the stages of the cell cycle and its checkpoints?

A

The cell cycle includes interphase (G1, S, G2 phases) where the cell grows and DNA replicates, and mitotic phase (mitosis and cytokinesis) where the cell divides. Checkpoints within the cell cycle ensure proper DNA replication and division, preventing errors that could lead to cell malfunction or disease.

80
Q

Explain each cell cycle checkpoint

A

The cell cycle is regulated by three main checkpoints that ensure proper progression and genomic integrity:
the G1 checkpoint checks for cell size, nutrient availability, and DNA integrity before allowing entry into the S phase
The G2 checkpoint ensures all DNA is accurately replicated and undamaged before entering mitosis.
The M checkpoint, or spindle checkpoint, ensures all chromosomes are correctly attached to the spindle apparatus and aligned at the metaphase plate before anaphase,

81
Q

What are the pathways and process of apoptosis?

A

Apoptosis occurs through intrinsic and extrinsic pathways. The intrinsic pathway involves mitochondrial signals, while the extrinsic pathway is triggered by death receptors. Apoptosis involves cell shrinkage, DNA fragmentation, and membrane blebbing, leading to the elimination of damaged or unnecessary cells without causing inflammation.

82
Q

What is apoptosis?

A

. Apoptosis involves cell shrinkage, DNA fragmentation, and membrane blebbing, leading to the elimination of damaged or unnecessary cells without causing inflammation.

83
Q

Describe the two pathways of apoptosis.

A

Apoptosis occurs via two pathways: the intrinsic and extrinsic pathways. The intrinsic pathway is triggered by internal signals like DNA damage, leading to mitochondrial release of cytochrome c and caspase activation.

The extrinsic pathway is initiated by external signals binding to death receptors, activating caspase-8. Both pathways converge on executioner caspases, resulting in cell death.

84
Q

What is the importance of the caspase enzyme in apoptosis?

A

Caspases are protease enzymes that play a crucial role in apoptosis by cleaving specific proteins to trigger cell dismantling. They are activated in a cascade, ensuring a controlled and efficient process of programmed cell death, which is essential for maintaining tissue homeostasis and preventing diseases like cancer.

85
Q

Explain what occurs after apoptosis.

A

After apoptosis, the cell undergoes a series of orderly events where it is dismantled into apoptotic bodies. These apoptotic bodies are then recognized and engulfed by phagocytic cells, such as macrophages, ensuring that the cellular debris is cleared efficiently without triggering inflammation or damage to surrounding tissues. This cleanup process helps maintain tissue homeostasis and prevents the release of potentially harmful substances from the dying cell.

86
Q

What happens if apoptosis fails?

A

If apoptosis fails, damaged cells remain in the tissue, impeding regeneration and increasing the risk of health complications such as cancer or tissue dysfunction.

87
Q

What is the relationship with apoptosis and cancer?

A

Apoptosis acts as a defence mechanism against cancer by eliminating abnormal cells. When apoptosis fails, these cells can grow rapidly when unchecked, contributing to the development and progression of cancer.

88
Q

What are the different types of potency in stem cells

A

Potency refers to a stem cell’s ability to differentiate into different cell types.

Totipotent cells can form any cell type, including extraembryonic tissues.

Pluripotent cells can become almost any cell type within the body.

Multipotent cells can differentiate into a limited range of related cell types, specific to certain tissues or organs.

89
Q

What is the difference between mesoderm, endoderm, and ectoderm?

A

Mesoderm, endoderm, and ectoderm are the three primary germ layers formed during embryonic development.
The mesoderm gives rise to muscles, bones, and the circulatory system.
The endoderm forms internal organs like the digestive and respiratory systems.
The ectoderm develops into the skin and nervous system.