lecture 3 ; cell structure, function, organelle and mitosis Flashcards
1
Q
- smallest living unit in the body
- obtain nutrients
- makes molecules needed to survive
- dispose of wastes
- maintain shape of cell
- replicate (mitosis)
without energy; all of that stops
A
cells
2
Q
cells organized into 3 areas
A
- plasma membrane
- cytoplasm
- nucleus
3
Q
- outer boundary
- separates the intracellular fluid within cell form extracellular fluid outside and between cells
- transport substances across the membrane
- fluid mosaic model (lipid bilayer)
A
plasma membrane
4
Q
4 methods of membrane transport
A
- simple diffusion
- osmosis
- facilitated diffusion
- active transport
5
Q
- contains most organelles
- lies internal to plasma membrane
- consists of cytosol, organelles and inclusions
A
cytoplasm
6
Q
controls cellular activities
A
nucleus
7
Q
- subunits of cells with specific function
- most cells contain the same basic organelles
- not all cells have all organelles in the same abundance
A
organelles
8
Q
relate to location at the interface of cell’s exterior and interior
- provides barrier against substances outside cell
- some plasma membranes act as receptors
- determines which substances enter or leave the cell
- membrane is selectively permeable
A
functions of the plasma membrane
9
Q
tendency of molecules to move down their concentration gradient
A
simple diffusion
10
Q
diffusion of water molecules across a membrane
A
osmosis
11
Q
movement of molecules down their concentration gradient through an integral protein
A
facilitated diffusion
12
Q
integral proteins move molecules across the plasma membrane against their concentration gradient
A
active transport
13
Q
mechanism by which particles enter cells
A
endocytosis
14
Q
cell eating
A
phagocytosis
15
Q
cell drinking
A
pinocytosis
16
Q
- plasma proteins bind to certain molecules
- invaginates and forms a coated pit
- pinches off to become a coasted vesicle
- this is the method by which insulin, other hormones, enzymes and low density lipoproteins enter cells
A
receptor- mediated endocytosis
17
Q
a mechanism that moves substances out of the cell
- substance is enclosed in a vesicle
- vesicle migrates to the plasma membrane
A
exocytosis
18
Q
- jelly like fluid in which other cellular elements are suspended
- consists of water, ions, and enzymes
A
cytosol
19
Q
constructed of proteins and ribosomal RNA; not surrounded by a membrane
- site of protein synthesis
- assembly of proteins called translation
- are the “assembly line” of the manufacturing plant
- attahed to ER
A
ribosome
20
Q
system of membrane walled envelopes and tubes throughout cytoplasm
A
endoplasmic reticulum
21
Q
ribosomes stud the external surfaces
A
rough Er
22
Q
consists of tubules in a branching network
-no ribosomes attached; therefore no protein synthesis
A
smooth er
23
Q
stack of 3 to 10 disc-shaped envelopes
- sorts products of er and sends them to proper destination
- products of rough er move through the ____ from the convex to the concave side
- “packaging and shipping” division of the manufacturing plant
A
Golgi apparatus
24
Q
membrane walled sacs containing digestive enzymes
- digest unwanted substances
- are the cells “demolition crew”
A
lysosomes
25
surrounded by double walled membrane
- generate most of the cells energy
- "power plant" of the cell
- release energy stored in chemical bonds and transfer energy to produce atp
- cells with high energy requirements have more
- most complex organelle
mitochondria
26
membrane walled sacs of oxidase enzymes
- enzymes neutralize free radicals and break down poisons
- break down long chains of fatty acids
- numerous in the liver and kidneys
- "toxic waste removal system"
peroxisomes
27
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"cell skeleton" an elaborate network of rods
contains 3 types of rods:
1. microtubules
2. microfilaments
3. intermediate filaments
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cytoskeleton
28
cylindrical structures made of proteins
microtubules
29
filaments of contractile protein actin
microfilaments
30
protein fibers
intermediate filaments
31
- a spherical structure in the cytoplasm
| - composed of centrosome matrix and centrioles
centrosome
32
paired cylindrical bodies
- consist of 27 short microtubules
- act in forming cilia
- necessary for karyokinesis
centrioles
33
found in liver cell and fat cells
lipid droplets
34
store sugar in the form of glycogen
glycosomes
35
- control center of the cell
- dna directs the cells activities
- provides instructions for protein synthesis
- nucleus is approximate 5 um in diameter
nucleus
36
two parallel membranes separated by fluid-filled space
- nuclear pores penetrate the nuclear envelope
- pores allow large molecules to pass in and out of the nucleus
nuclear envelope
37
- "little nucleus" in the center of the nucleus
- contains parts of several chromosomes
- site of ribosome subunit assembly
nucleolus
38
DNA double helix is composed of 4 subunits
Thymine, adenine, cytosine and guanine
39
dna plus protein molecules form
chromatin
40
each cluster of dna and histone proteins is a
nucleosome
41
active region of dna where dan's genetic code is copied onto mRNA in transcription
extended chromatin
42
- tightly coiled nucleosomes
| - inactive form of chromatin
condensed chromatin
43
highest level of organization of chromatin
- contains a long molecule of DNA
- typical human cells contains 46 chromosomes
chromosomes
44
series of changes a cell undergoes
cell life cycle
45
Cell life cycles
1. interphase g1
2. S phase
3. G2 phase
4. mitosis
6. cytokinesis
7. prophase
8. metaphase
9. anaphase
10. telophase
11. cytokinesis
46
G1 phase
- first part
- cell metabolically active
- -makes protein and grows rapidly
- variable in length from hours to years
- centrioles begin to replicated near the end of G1
interphase
47
DNA replicates itself
| -ensures that daughter cells receive identical copies of the genetic material
S (synthetic) phase
48
Growth 2
- centrioles finish coping themselves
- enzymes needed for cell division are synthesized in G2
-During these phases cell carries on normal activities
G2 phase
49
cells divide during the stage
| -follows interphase (g1, s and G2)
M (mitotic) phase
50
division of the nucleus during cell division
| -chromosomes are distributed to the two daughter nuclei
mitosis
51
division of the cytoplasm
| -occurs after the nucleus divides
cytokinesis
52
first and longest stage of mitosis
- early ___ ; chromatin threads condense into chromosomes
- chromosomes are made up of 2 threads called chromatids
- chromatids are held together by centromere
- certriole pairs separate from one another
- the mitotic spindle forms
prophase
53
chromosomes are made up of 2 threads
chromatids
54
chromatids are held together by
centromere
55
centrioles continue moving away from each other
| -nuclear membrane fragments
late prophase
56
second stage of mitosis
- chromosomes cluster at the middle of the cells
- centromeres are aligned along the equator
metaphase
57
the 3rd and shortest stage of mitosis
| -centromeres of chromosomes split
anaphase
58
begins as chromosomal movement stops
- chromosomes at opposite poles of the cell uncoil
- resume threadlike extended- chromatin form
- a new nuclear membrane forms
telophase
59
completes the division of the cell into 2 daughter cells
cytokinesis
60
they are temporary structures in the cell. can contain energy in the form of glycogen or lipids
inclusions
61
proteins or minerals
crystals
62
hemoglobin or melanin
pigments
