Cellular Organization (chapter 3) Flashcards

Question

Golgi

Answer 1

-stack of cisternae with an associated transport vesicles -near nucleus but not attached -functions: A.modifies and packages secreations B. renews or modifies the cell membrane C. packages enzymes within vesicles to create a temporary digestive organelle called the lysosome -transport vesicles from RER dock on cisternae face or forming face of golgi -proteins (and glycoproteins) are modified (phosphate, carbohydrates, or lipids attached, polypeptides, refolded) -modified proteins transit between cisternae via vesicles from cis face (forming) to trans face (maturing) and are concentrated and sorted by final function and destination -at trans face proteins are packaged into one of three types of vesicles for transport

Answer 2

A. secretory vesicles: carry products to be exocytosed for use outside the cell B. membrane renewal vesicles: carry products to be incorporated into the plasma membrane C. lysosomes: temporary organelles membrane bound sacs of digestive enzymes

Answer 3

-digestion center for large molecules or structures, cell can have many -functions: A. cellular cleanup: remove and recycle damaged organelles and extra molecules B. break down material and objects that have been endocytosed -endosomes or phagosomes containing endocytosed things and organelles and molecules targeted for destruction are fused with the lysosome and enzymatically broken down -some solutes diifuse into cytoplasm for use remaining debris are exocytosed -failure of lysosomes causes build up of cells that eventually prevents cell functions e.g Tay Sach's disease

Answer 4

-membrane sac containing oxidases and catalases to neutralize free radicals -free radicals (e.g H2O) form during catabolism of organic molecules -peroxisomes not made by golgi enzymes produced by free ribosomes, cell can have many

Answer 5

-cylindrical structure composed of protein digesting enzymes called proteases -functions to degrade and recycle damaged, denatured or abnormal proteins -hydrolyzes peptide bonds of proteins tagged with ubiquitin to recycle amino acids, cell can have many

Answer 6

-sausage shaped with double membrane -outer membrane: smooth -inner membrane: folded folds called cristae -center= matrix (fluid) -aerobic cellular respirations occurs on surface of cristae where glucose is catabolized creating CO2 and H2O waster to convert ADP into ATP -mitochondria supply most of cell's energy (~95%: 2ATP per glucose w/o mitochondria 36 ATP per glucose with) -have their own DNA -can replicate independent of the cell -mitochondrial DNA is maternal

Answer 7

-control center of cell: directs proteins synthesis (proteins are responsible for structure and function of cell) -contains DNA: genetic material -most cells have one, exceptions skeletal muscle (many), RBCs (none) -surrounded by nuclear envelope: double membrane, outer layer connected to ER -has nuclear pores with regulator proteins that control exchange of molecules between cytoplasm and nucleus -inside is DNA floating in nucleoplasm with nucleotides, RNA and protein enzymes -in non dividing cells DNA is loose called chromatin -open form of DNA allows access to information to direct protein synthesis

Answer 8

-inside a nucleus is DNA floating in nucleoplasm with nucleotides, RNA and protein enzymes -in non dividing cells DNA is loose called chromatin -open form of DNA allows access to information to direct protein synthesis =DNA in chromatin is organized into nucleosomes:DNA wound around histone proteins

Answer 9

prevent tangling and breakage and reduce amount of space DNA takes up

Answer 10

chromatin is tightly wound into individual visible bundles of DNA called chromosomes (23 pairs in humans)

Answer 11

-DNA contains genes Genes = functional units of heredity -encode for a product: RNA or protein Humans have ~30 thousand potential genes (most encode enzymes for metabolism) -this is only 1.5% of total DNA -remainder is involved with control of genes, some appears to be junk (25%) -noncoding parts of DNA (non-genes) is highly variable one person to next -variability allows for identification of an individual by DNA fingerprinting -in order for a gene to be expressed (used to make a product) it must be unwound from the histone proteins so it can be read -disassembly of the nucleosomes and unwinding of the DNA to copy the information is called gene activation

Answer 12

-language of the DNA that is read off a gene in order to assemble a protein -3 bases of DNA = 1 codon -each codon gives the instructions for one amino acid -a gene= all the codons for all the amino acids in one protein in the correct order with control regions

Answer 13

-making an RNA copy of a DNA gene -occurs in nucleus

Answer 14

=making a protein using the mRNA blueprint -occurs in the cytoplasm on free ribosomes or on fixed ribosomes

Answer 15

-two ribosomal subunits -mRNA -tRNAs carrying amino acids

Answer 16

-life span cell depends on type of cell -all cells eventually die -some cells must divide to make cells to replace dying cells: function of stem cells -to divide, DNA must be replicated and equally distributed between the stem cell and new daughter -most cells spend very little time dividing in an adult instead are performing cellular functions

Answer 17

=nuclear division -Once G1 phase S phase and G2 phase of interphase are complete mitosis begins

Answer 18

controlled to cell death, lysosomes are defused to prevent damage to other cells

Answer 19

1. Interphase: period of time that a cell performs its normal functions -if a cell never divides, it remains in G0 phase of interphase -if the cell is preparing to divide, it will go through 3 stages in interphase: A. G1 phase: cell doubles organelles and synthesizes enough cytoplasm for two cells B. S phase: cell duplicates DNA C. G2 phase: copious protein synthesis: cell generates enough enzymes for two cells, centrioles are replicated

Answer 20

-S phase of interphase -only performed by cells preparing for division -will be followed by mitosis

Cellular Organization (chapter 3) Flashcards

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