Lecture 4: The Cell Flashcards Preview

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Flashcards in Lecture 4: The Cell Deck (28):
1

Properties and Actions of cells

growth, reproduction, absorption, metabolism, excretion and secretion, excitability, conductivity, contractibility

2

Chemical Composition of cell

85% water
10% protein
2% lipid
1.5% inorganic matter
1.5% other substances and carbohydrates

3

Important organelles

golgi apparatus, endoplasmic reticulum (smooth and rough), free ribosomes, mitochondria, lysosomes, peroxisomes, microtubules and microfilaments

4

Endoplasmic reticulum (ER)

-mesh of interconnected membranes; used for protein synthesis and transport
-connects to the nuclear envelope/membrane through which the mRNA, the blueprints for proteins, travelto the ribosomes

5

mitochondria

-"power house" of cells
-have a variety of enzymes and co-enzymes
-oxidation of nutrients to CO2, ATP, and H2O

6

lysosomes

-small membrane-bound bags involved in digestion and detoxification
-contain 50 different digestive enzymes
-break up the material into smaller and simpler products that the cell can use
-digest worn-out cell components and pathogens engulfed by WBC's

7

cytoskeleton

-organized network of three primary protein filaments: microtubles, actin filaments, and intermediate fibers
-primary importance: cell motility
-maintain cell shape and the internal movement of cell organelles
-cell locomotion and muscle fiber contraction could not take place without the cytoskeleton

8

microtubules

assist in transport of molecules within some cells

9

microfilaments

assist with cell motility

10

actin and intermediate fibers

assist in muscle contractions

11

Nucleus

-largest organelle
-surround by a double membrane: nuclear envelope
-nuc. envelope is permeated with gates called nuclear pores
-pore are routes by which genetic messages pass into the cytoplasm
-nucleus=info centre

12

Nucleolus

area of nucleus (looks like a dark dot) that contains chromosomes

13

chromosomes

contain heredity information, made of DNA and proteins

14

Chromatin

fragments of chromosomes, coiled together to form one

15

Ribosomes

-protein factories
-in the nucleus, DNA's instructions are transcribed into a messenger molecule of ribonucleic acid called mRNA
-the code in a strand of mRNA is translated into a protein by ribosomes, in the cytoplasm

16

Cell Membrane

-double layer of lipid molecules interspersed with protein molecules
-maintains cell integrity
-functions as a semi-permeable barrier
-controls what goes in and out of cell
-usually semi-permeable

17

Types of transport across CM

diffusion, passive transport, and active transport

18

diffusion

-method of movement of substances to cross the membrane directly
-water, CO2, and O2 are among the few simple molecules that an cross CM by diffusion (diffusion aka osmosis)

19

Osmosis

-diffusion of water through a semipermeable membrane from high concentration to low
-used for filtering urine through kidneys and movement of water across intestine walls

20

Facilitated diffusion

does not use energy, membrane or proteins pick up molecules and coarry them across the membrane from high to low concentration

21

Active transport

allows molecules to move against their conc. gradient, requires energy

22

endocytosis

energy requiring process where cell membrane surrounds molecules, forming a pocket which becomes a vacuole in the cytoplasm
-types include phagocytosis and pinocytosis

23

phagocytosis

-membrane surrounds large particles, forms a pocket, then a vacuole
-this is how amoeba and WBCs feed

24

pinocytosis

-literally means cell drinking
-membrane surrounds a liquid, forms a pocket, then a vacuole

25

exocytosis

energy requiring process where a vacuole containing large molecules joins with the membrane, makes an opening, and squeezes the molecules out of the cell

26

vesicle-mediated transport

vesicles and vacuoles that fuse with the cell membrane may be utilized to release or transport chemicals out of the cell or to allow them to enter

27

Tight Junctions

-the portion of the cell exposed to the lumen is called its apical surface
-the rest of the cell (sides and base) make up the basolateral surface

28

Gap Junctions

because ions can flow through them, gap junctions permit changes in membrane potential to pass from cell to cell