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level: 1.2 Cell Structure

Questions and Answers List

level questions: 1.2 Cell Structure

QuestionAnswer
What are the features of a prokaryote (and function) (6)Nucleoid: region in cytoplasm where DNA is located, (DNA strand is circular = genosphere) Plasmids: autonomous circular DNA molecules that can be transferred bw bacteria (horizontal gene transfre) 70S ribosomes: RNA + protein for translation Cell wall: outer covering made of peptidoglycan to maintain shape and prevent bursting Slime capsule: thick polysacch layer for protection against dessication (drying out) and phagocytosis Flagella: long progections w/ motor protein for movement (flagellum) Pili: hair like extensions to stick to surfaces / mediates bacterial conjugation
What are plasmids able to do? (4)plasmids are autonomous molecules of circular DNA they can be transferred bw bacteria by BACTERIAL CONJUGATION mediated with a sex pilus = exchange of genetic characteristics
How do pros asexually reproduce?by binary fission DNA is copied as a response to a replication signal 2 DNA loops attach to the membrane membrane elongates and pinches off by cytokinesis = 2 distinct cells
In what ways to pros and euks differ? (4)DNA pros: naked + circular DNA euks: bound to protein + linear DNA Organelles pros: no membrane bound organelle + 70S ribosomes euks: membrane bound organelles + 80S ribosomes Reproduction pros: binary fission + haploid euks: mitosis and meiosis + diploid Average size pros: small (1-5 micrometers) euks: large (10-100 micrometers)
What are eukaryotes? (4)complex cells with a nucleus compartmentalised cellular structure membrane bound organelles believed to have come from pros by endosymbiosis
What are organelles?specialised sub structures in cells to do a specific function
What are the 4 types of eukaryotes?protista: unicellular / multicellular without specialised tissue fungi: chitin cell wall and are heterotrophs plantae: cellulose cell wall and are autotrophs Animalia: no cell wall and are heterotrophs
Draw an animal cell (9)mitochondria Smooth + rough ER cytoplasm cell membrane ribosomes 80s golgi apparatus nucleus nucleolus Lysosome
Draw a plant cell (10)golgi apparatus smooth and rough ER nucleus ribosomes 80S cell wall cellulose chloroplast vacuole mitochondria cell membrane cytoplasm
Which organelles are present in both pro and euk?ribosomes cell membrane cytoplasm
Which organelle is only present in animal cells?lysosome
Which organelles are only present in plant cells?chloroplasts vacuole cell wall (cellulose)
What is the structure and function of ribosomes? (3)2 subunits made of RNA and protein (80s in euk and 70s in pro) site of polypeptide synthesis (translation)
What is the structure and function of the cell membrane? (2)phospholipid bilayer embedded with proteins semi-permeable + selective barrier around the cell
What is the structure and function of the nucleus? (3)a double membrane structure with pores has an inner region (nucleolus) stores genetic material (DNA) as chromatin and nucleolus is site of ribosome assembly
What is the structure and function of the endoplasmic reticulum? (3)a membrnae network that can be smooth / rough (w ribsomes) transports materials between organelles smooth ER = lipids rough ER = proteins
What is the structure and function of the golgi apparatus?a group of vesicles and folded membranes near cell membrane sorts and exports secretory products
What is the structure and function of a mitochondriondouble membrane structure = inner membrane highly folded site for aerobic resp = ATP production
What is the structure and function of peroxisome?membranous sac with catabolic enzymes catalyses breakdown of toxic substances (H2O2)
What is the structure and function of centrosome?microtubule organizing centre with paired centrioles in animal cells radiating microtubules = spindle fibres which help with cell division (mitosis and meiosis)
What is the structure and function of chloroplasts?double membrane structure with internal stacks of discs site for photosynthesis = make organic mols that are stored in plastids
What is the structure and function of a vacuole?fluid filled internal avity surrounded by tonoplast maintains hydrostatic pressure
What is the structure and function of cell walls?outer covering made of cellulose provides support + mechanical strength and stops excess water uptake
What is the structure and function of lysosomes?membranous sacs filled with hydrolytic enzymes breaks down macromolecules
What are the two types of cells?pros: have no nucleus ( archaea + bacteria) euks have a nucleus (protista, fungi, plantae and animalia)
What are the two types of prokaryotes?archaea = found in extreme environments (high temps = extremophiles) Eubacteria = bacteria in pathogenic forms (E. Coli)