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52 Cards in this Set
- Front
- Back
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What are the general characteristics of the eucaryotic cell? |
- DNA housed in nucleus
- algae, protozoans, fungi, plants, animals - typically larger and more complex than prokaryotic cells - genetic material is organized into chromosomes by closely associating with histones and other proteins - contains membrane bound organelles |
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What is the difference between a plant cell and an animal cell?
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- animal and plant cells both have a nucleus, a cytoplasm, and a cell membrane.
- Plant cells also have a large cell vacuole, chloroplasts, a cell wall and a regular shape. - Animal cells have small vacuoles, no cell wall, varied shapes, and the absence of chloroplasts characterize animal cells. |
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What are histones? What are the functions of histones?
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special chromosomal proteins found only in eukaryotes which package and structure DNA. They are the chief protein components of chromatin, act as spools around which DNA winds and play a role in gene regulation.
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What is the structure of the flagella and cilia in the eucaryotic cell?
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- contain cytoplasm and enclosed by plasma membrane
- arranged in 9 pairs of doublet microtubles + pair of central microtubles. - microtubules composed of tubulin protein. |
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What is/are the difference between the flagellum of eukaryotes and prokaryotes?
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- Eukaryotic flagella move in a wave-like manner but prokarytic flagella rotate like a rotor blade.
- In prokaryotes made of flagelin (protein). made of microtubles in Eukaryotes. |
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The cell walls of algae and all plants are composed of what substance?
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Cellulose
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Most fungi have cell walls composed of what molecule?
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Chitin
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Yeasts have cell walls composed of what molecules?
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glucan and mannan (polysacharides)
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What is a pellicle?
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flexible outer covering on Protozoans, instead of a typical cell wall.
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What are the components of the eucaryotic plasma membranes?
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Phospholipids, Proteins, carbohydrates, sterols.
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What role does the carbohydrates of the eucaryotic membrane play?
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Carbohydrates function in cell to cell recognition and provides adherence for bacteria
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What role does the sterols of the eucaryotic membrane play?
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Sterols confer the ability of the membranes to resist lysis due to increased osmotic pressure.
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Explain endocytosis.
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Endocytosis is the packaging of extracellular material for import into the cell.
Membrane surrounds a particle and encloses it and brings it into the cell. 3 types: receptor-mediated (specific for target molecule) phagocytosis (cell eating) pinocytosis (cell drinking) |
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What are pseudopods?
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In Phagocytosis the cell extends a pseudopod around a solid object, engulfs object forming a vesicle. Vesicle fuses with lysosomes to digest object.
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Explain exocytosis.
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vesicle within the cell fuses with the plasma membrane and releases contents into the extracellular space.
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What membrane transport mechanisms occur in the eucaryotic cell?
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Passive processes include:
- Simple diffusion - facilitated diffusion - osmosis Active processes include: - active transport - group translocation |
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What are ligands?
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Many ion channels open or close in response to binding a small signaling molecule or "ligand". Some ion channels are gated by extracellular ligands; some by intracellular ligands. In both cases, the ligand is not the substance that is transported when the channel opens. (receptor-mediated endocytosis)
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What are receptors?
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binding of ligand (target) to receptor triggers internalization of receptor and target in a coated vesicle. Receptors can be recycled. (receptor-mediated endocytosis)
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What is cytoplasm?
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consists of cytoplasmic fluid (cytosol), organelles and cytoskeletal elements.
everything between plasma membrane and nucleus. |
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What is a cytoskeleton?
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cellular "scaffolding" or "skeleton" contained within the cytoplasm and is made out of protein.
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What are cytoskeletal elements and function?
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contains:
Microfilaments: made of actin proteins. Cell mobility and contraction Intermediate filaments: provide cell stability, anchor proteins to plasma membrane Microtubles: made of tubulin, maintain cell shape. Form mitotic spindle during cell division. Transport substances within cell. |
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What is the function of the nucleus?
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- houses the cells hereditary information (DNA).
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What is the composition of the nuclear envelope?
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double membrane (resembles plasma membrane in structure). Tiny channels called nuclear pores.
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What are nuclear pores?
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tiny channels in the nuclear envelope that allow the nucleus to communicate with the cytoplasm.
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What is nucleoplasm?
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matrix within the nuclear envelope
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What is the function of the nucleolus?
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center for synthesis of ribosomal RNA. Inside the Nucleus.
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What is the nucleosome?
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DNA wrapped around 8 histones; basic structural units of chromosome
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What is chromatin?
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DNA and it's associated proteins (histones) in the uncondensed form
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What is a chromosome?
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coiled chromatin in short, rod-like bodies during nuclear division (mitosis or meiosis)
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What is a centromere?
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constricted center region of a mitotic chromosome that holds sister chromatids together.
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What are telomeres?
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Region at the end of eukaryotic chromosome.
Telomerase: Protects ends of DNA from shortening. The older the cell the shorter the telomere. |
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What is the endoplasmic reticulum?
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a network of flattened membrane sacs or tubes that is an extension of the nuclear envelope.
Smooth ER and Rough ER |
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What is the function of the smooth ER and rough ER?
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Smooth ER: no ribosomes attached; lipid and steroid synthesis, detoxify drugs and harmful substances
Rough ER: have ribosomes attached; to process and sort synthesized proteins; exports proteins |
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What type of ribosomes are found in eucaryotic cells? Where are they localized?
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80s ribosome
- Bound to rough ER - Free in the cytosol |
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What are the 2 subunits of the eucaryotic ribosomes and how many molecules of rRNA are ontained in each subunit?
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- large subunit (60S): 3 rRNAs and 50 proteins
- small subunit (40S): 1 rRNA and 33 proteins - 18S is ribosomal RNA??? |
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What is the composition of the ribosomes of the chloroplasts and mitochondria?
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70S ribosome, can self replicate on it's own within the cell.
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What is the structure and function of the Golgi apparatus/complex?
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- consists of 4-20 flattened sacs (cisterns) stacked on top of the other with expanded ends.
- modifies proteins: glycoprotein, lipoprotein, etc. - secretory proteins sent out of cell via exocytosis - proteins membrane bound or to remain in vesicle (lysosome) |
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What is the structure, function, and characteristics of the mitochondrium?
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- power house, function is to synthesize ATP during cellular respiration
- double membrane similar to plasma membrane - smooth outer membrane - inner membrane in a series of folds called cristae. Increase area for chemical reaction to occur. matrix: center of mitochondrium |
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What is the structure, function, and characteristics of the chloroplast?
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- photosynthesis
- contained in algae and green plants - membrane-bounded structures that contain the pigment chlorophyll and the enzymes required for photosynthesis - 70S ribosome |
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What cells contain chloroplast?
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cells of Algae and green plants
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What are thylakoids?
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chlorophyll is contained in flattened membrane sacs called thylakoids.
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What is a grana?
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stacks of thylakoids
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What is chlorophyll?
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Green pigment in plants and algae essential to photosynthesis.
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What is photosynthesis?
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the conversion of light energy into chemical energy by living organisms.
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Who is Lynn Margulis?
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championed the Endosymbiotic Hypothesis which held that eukaryotic mitochondria and chloroplasts were originally prokaryotes.
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What ist he endosymbiotic hypothesis?
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Mitochondria were descended from aerobic bacterium. Chloroplasts from phytosynthetic cyanobacterium. Eubacterium engulfed by eukaryotic ancestor and ends up surrounded by 2 membranes.
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What is aerobic respiration?
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Aerobic respiration requires oxygen in order to generate energy (ATP).
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What are the evidences to support the endosymbiotic hypothesis?
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- Mitochondria have their own circular chromosomes encoding genes to replicate their DNA
- reproduce by binary fission, like bacteria - same size as bacteria - have their own ribosomes for protein synthesis, very similar to bacterial ribosomes - each surrounded by a double membrane |
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What is the structure and function of the lysosomes?
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membrane bound vesicles which contain hydrolytic enzymes. They digest foreign substances and cell debris; can digest bacteria
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What is the structure and function of the centrioles?
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- found in pairs
- direct the formation of the mitotic spindle during cell division - contribute to structure of cilia and flagella - 9 + 0 array. 9 triplets. |
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What is the mitotic spindle?
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An array of microtubules and associated molecules that forms between the two poles of a eukaryotic cell during mitosis and serves to move the duplicated chromosomes apart.
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Be able to compare and contrast the differences between prokaryotes and eukaryotes.
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Prokaryotic cells:
Most primitive, earliest form of life Do not have a pre-defined nucleus Chromosomes are dispersed in the cytoplasm Contain no membrane-bound organelles Have circular chromosomes and lack histone proteins Most metabolically diverse Small - typically 0.2-2.0 micrometers in diameter Have a primitive cytosketetal structures or don't have a cytoskeleton at all Smaller (70S) ribosomes Don't undergo meiosis but reproduce sexually by the transfer of DNA fragments through conjugation Eukaryotic cells: More complex, evolved organsims Contain true nuclei in which chromosomes are compacted as chromatin Contain membrane-boundorganelles Have linear DNA and contain histone proteins Larger - typically 10-100 micrometers in diameter Have a complex cytosketeton Larger (80S) ribosom Reproduce sexually with the use of meiosis |
