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Intro to Biology Flashcards
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Intro to Biology Flashcards
Intro to Biology Flashcards
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1
Question
What is evolution according to the text, and how do Lamarck's and Darwin's views differ?
Answer
Evolution is the process by which different kinds of living organisms developed from earlier forms during Earth's history. Lamarck proposed that species spontaneously generate and mutate based on needs and functionalities. Darwin proposed evolution based on survival of the fittest mutations.
2
Question
What are the main characteristics that define a living organism?
Answer
Main characteristics of living organisms include: being made of cells, requiring energy (food), reproducing to form species, maintaining homeostasis, being organized, responding to the environment, growing and developing, and exchanging materials like water, wastes, and gases with surroundings.
3
Question
What is the difference between prokaryotic and eukaryotic organisms?
Answer
Prokaryotic organisms are unicellular, lack a nucleus and many specialized organelles, and include bacteria. Eukaryotic organisms have cells with a true nucleus and membrane-bound organelles, including protists, fungi, plants, and animals.
4
Question
What is the primary function of the cell or plasma membrane, and what is its basic structure?
Answer
The cell or plasma membrane controls what enters or leaves the cell and surrounds the outside of all cells. It is composed of a double layer (bilayer) of phospholipids and proteins, with carbohydrate chains on the outside.
5
Question
How does the nucleus control cell activities, and what are some of its key features?
Answer
The nucleus controls the normal activities of the cell by containing DNA in chromosomes, which carry genes that determine cell characteristics. It is bounded by a nuclear envelope (a membrane) with pores and is usually the largest organelle in the cell.
6
Question
Describe the cytoskeleton and its components, including their roles in the cell.
Answer
The cytoskeleton helps the cell maintain its shape and assists in moving organelles around. It is made of proteins; microfilaments are threadlike and made of actin, while microtubules are tube-like and made of tubulin.
7
Question
What unique features do mitochondria have, and why are they important in the cell?
Answer
Mitochondria have a double membrane with a folded inner membrane called cristae that increases surface area for chemical reactions. They contain their own DNA and are the site of cellular respiration, generating cellular energy (ATP). More active cells have more mitochondria, and inheritance of mitochondria is maternal.
8
Question
What are the two main types of Endoplasmic Reticulum (ER) and how do their functions differ?
Answer
The two main types of ER are Rough ER and Smooth ER. Rough ER has ribosomes on its surface and makes membrane proteins and proteins for export out of the cell. Smooth ER lacks ribosomes, makes cell products used inside the cell like membrane lipids (steroids), regulates calcium in muscle cells, and destroys toxic substances in the liver.
9
Question
How do ribosomes contribute to protein synthesis, and where can they be found in the cell?
Answer
Ribosomes, made of proteins and rRNA, are the 'protein factories' that join amino acids to make proteins through protein synthesis. They can be attached to the Rough ER or be free (unattached) in the cytoplasm.
10
Question
What roles do the Golgi bodies perform in the cell?
Answer
Golgi bodies modify, sort, and package molecules received from the ER for storage or transport out of the cell. They have a receiving (cis) face and a shipping (trans) face, from which transport vesicles carrying modified proteins pinch off.
11
Question
What is homeostasis and why is it essential for cells?
Answer
Homeostasis is the maintenance of the relative stability of the internal physical and chemical environment within a range compatible with cellular function. It is essential because it ensures cells have a constant supply of oxygen, glucose, minerals, ions, and efficient waste removal necessary for survival.
12
Question
Describe the components involved in a homeostatic control system.
Answer
The five components are: 1) Sensor, which detects changes; 2) Afferent pathway, which transmits signals to the control center; 3) Integration center or comparator, which processes the information; 4) Efferent pathway, which carries signals from the control center; and 5) Effector organ(s), which respond to restore balance.
13
Question
How does the nervous system contribute to homeostasis?
Answer
The nervous system maintains homeostasis by sensing deviations from set points through receptors, sending nerve impulses to regulating centers in the brain (central nervous system), which then direct effectors to produce adaptive responses. Key brain areas involved include the hypothalamus, medulla oblongata, and pituitary gland. The peripheral nervous system, particularly the autonomic nervous system, controls internal organs to adjust bodily functions.
14
Question
What roles do hormones play in the endocrine system related to homeostasis?
Answer
Hormones secreted by endocrine glands regulate metabolism, development, and function of body cells and systems. They influence processes such as reproduction, muscle metabolism, neural metabolism, cardiovascular regulation, inflammatory responses, and fluid balance, thus maintaining homeostatic balance across multiple body systems.
15
Question
Explain the difference between negative and positive feedback in physiological control systems.
Answer
Negative feedback causes a physiological variable to change in the opposite direction of its initial deviation from a set point, helping maintain stability. Positive feedback amplifies the initial change, pushing the variable further from the set point, often to complete a specific biological process.
16
Question
What are the three main checkpoints that control the cell cycle?
Answer
The three main checkpoints are the G1 checkpoint (before S phase), the G2 checkpoint (between G2 and M phase), and the M checkpoint.
17
Question
How does bacterial reproduction differ from eukaryotic cell division, and what processes allow genetic variation in bacteria despite no mitosis or meiosis?
Answer
Bacteria reproduce asexually through binary fission, which creates identical daughter cells without mitosis or meiosis. Genetic variation occurs through horizontal gene transfer mechanisms including transformation (uptake of genetic material from the environment), transduction (transfer via viruses), and conjugation (direct transfer between prokaryotes).
18
Question
What are the four phases of mitosis, and what key events occur in each?
Answer
1. Prophase: Chromosomes condense, spindle forms, nuclear envelope breaks down. 2. Metaphase: Chromosomes align at cell equator. 3. Anaphase: Sister chromatids separate and move to opposite poles. 4. Telophase: Nuclear envelopes re-form around chromatids, chromosomes unwind.