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62 Cards in this Set
- Front
- Back
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What is the stucture that makes up every living thing?
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the cell
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Anton van Leeuwenhoek
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1674- He used a single-lens microscope to observe pond water and found a tiny world of living organisms
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Anton van Leeuwenhoek
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1674- He used a single-lens microscope to observe pond water and found a tiny world of living organisms
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Robert Hooke
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1665- He observed under a microscope that a cork seemed to be made of thousands of tiny, empty chambers or "cells"
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Matthias Schleiden
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1838- German botanist who concluded that all plants are made of cells
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Theodor Schwann
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1839- German biologist who concluded that all animals are made of cells
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Rudolph Virchow
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1855- He concluded that new cells could be produced only from the division of existing cells
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What are the 3 concepts of the cell theory?
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1) All living things are composed of cells
2) Cells are basic units of stucture and function of living things 3) New cells are produced from existing cells |
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Why are electron microscopes capable of revealing details smaller than those of light microscopes?
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The wavelengths of electron micros are much shorter than those of light micros.
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Prokaryotes
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-organisms whose cells lack a nucleus
-grow and reproduce -simpler than eukaryotic cells -example= bacteria |
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Eukaryotes
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-organisms whose cells contain a nucleus
-more comple than prokaryotes -examples= plants, animals, fungi, and protists |
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What is an organelle?
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a specilized structure that performs important cellular functions within a eukaryotic cell
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What is the function of the nucleus?
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contains all of the cell's DNA and with it the coded instructions for making proteins and other important molecules
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What important molecules does the nucleus contain?
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DNA, RNA, and proteins
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The grandular material visible with the nucleus is called____
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chromatin
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What does chromation consist of?
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DNA bound to protein
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What are chromosomes?
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threadlike stuctures that contain the genetic information that is passed from one generation of cells to the next
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Most nuclei contain a small, dense region known as the____
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nucleolus
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What occurs in the nucleolus?
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-assembly of ribosomes begins
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What is the nuclear envelope?
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allows material to move into and out of the nucleus; layer of two membranes that surrounds the nucleus of a cell
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What are ribosomes?
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-small particles of RNA and protein found in the cytoplasm
-produce proteins by following coded instructions that come from the nucleus |
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What is the difference between rough ER and smooth ER?
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-rough ER has ribosomes found on its surface
-smooth ER does not |
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Golgi Body (apparatus)
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- modifies, sorts, and packages proteins and other materials from the ER for storage in the cell
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Lyosomes
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-contain enzymes that help synthesize lipids
-break down organelles that have outlived their usefulness -contain enzymes that break down lipids, carbs, and proteins |
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Vacuoles
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saclike structures that store materials such as water, salts, proteins, and carbs
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What is the role of the central vacuole in plants?
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the pressure makes it possible for plants to support heavy structures such as leaves and flowers
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How does the contractile vacuole in a paramecium help maintain homeostasis?
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pumps excess water out of the cell and therefore controls the water content
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What are mitochondria?
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organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use
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Biologist Lynn Margulis has suggested that mitochondria and chloroplasts are descendants are what kind of organisms?
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prokaryotic endosymbionts
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Cytoskeleton
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-a network of fibers located throughout the cell's cytoplasm
-these fibers give support to the cell and help the cell maintain shape |
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Microtubules
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-hollow-shaped
-made up of proteins known as tubulins -help with cell shape -build cilia and flagella -help w/ cell division- form mitotic spindles which seperate chromosomes -help w/ cell division- from centrioles which help organize division |
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Microfilaments
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-thread-like
-made up of proteins known as actin -form networks and framework that support the cell -help the cell move |
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Cell Membrane
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-regulates what enters and leaves the cell
-provides protection and support |
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The core of nearly all cell membranes is a double-layered sheet called the_____
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lipid-bilayer
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What is the main function of the cell wall?
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provide support and protection of the cell
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What are plant cell walls mostly made of?
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cellulose- a tough carbohydrate fiber
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What is the concentration of a solution?
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-mass and soulte in a given volume of solution
-mass divided by volume |
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Diffusion
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-process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
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What is meant when a system has reached equilibrium?
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the concentration of the solute is the same throughout a system
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What does it mean that biological membranes are selectively permeable?
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some substances can pass across them and others cannot
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Osmosis
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the diffusion of water through a selectively permeable membrane
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On which side of a selectively permeable membrane does osmosis exert a pressure?
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-exerts an osmotic pressure on the hypertonic side
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What is facilitated diffusion?
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movement of specific molecules across cell membranes through protein channels
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What is the role of protein channels in the cell membrane?
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act as carriers making it easy for certain molecules to cross
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The energy-requiring process that moves material across a cell membrane against a concentration difference is called_____
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active transport
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Endocytosis
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-process by which a cell takes material into the cell by infolding of the cell membrane
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Phagocytosis
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-process in which extensions of cytoplasm surround an engulf large particles an take them into the cell
-a form of active transport due to requiring energy |
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Pinocytosis
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-process by which a cell takes in liquid from the surrounding enviroment
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Exocytosis
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-process by which a cell releases large amounts of materials
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During endocytosis, what happens to the pocket in the cell membrane when it breaks loose from the membrane?
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forms a vacuole within the cytoplasm
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Hypertonic
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- water moves from higher concentration (inside the cell) to lower concentration (outside the cell)
-plamolysis= cell shrinks |
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Isotonic
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-water moves out/in at the same rate
-equilibrium= cell doesn't change shape |
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Hypotonic
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-water moves from higher concentration (outside the cell) to lower concentration (inside the cell)
-cytolcysis= cell grows & bursts |
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A single-celled organism is called_____
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a unicellular organism
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Cell Specialization
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-process in which cells develop in different ways to perform different tasks
-the human body contains many different cell types -some cells are specialized to enable movement |
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What are the four levels of organization in a multicellular organism?
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individual cells
tissues organs organ systems |
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What is tissue?
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-a group of similar cells that perform a particular function
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What are the four main types of tissue in most animals?
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muscle
epithelial nervous connective tissue |
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Groups of tissues that work together to perform a specific function are called a(n)______
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organ
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What kinds of tissues can be found within the muscle of your body?
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nervous tissues and connective tissues
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What is an organ system?
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a group of organs that work together to perform a specific function
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