Ch. 4 Cell Structure & Functions Flashcards
1
Q
what is a cell?
A
the most basic unit of structure capable of carrying all processes of life
2
Q
Robert Brown
A
1st to identify the nucleus in plant cells
3
Q
Theodor Schwann
A
1st to state that animals are made up of cells and cell parts
4
Q
Rudolph Virchow
A
said that all cells come from preexisting cells
5
Q
Matthias Schleiden
A
1st to state all plants are made up of cells and cell parts
6
Q
Robert Hooke
A
1st to observe a thin slice of cork & called the compartments “cells”
7
Q
The Cell Theory (1)
A
All living organisms are composed of 1 or more cells
8
Q
The Cell Theory (2)
A
The cell is the most basic structural unit having the basic properties of life
9
Q
The Cell Theory (3)
A
All cells come from preexisting cells
10
Q
4 main functions of cells
A
- take in nutrients
- convert nutrients to energy
- get ride of waste
- to reproduce
11
Q
Prokaryote
A
cells that have no nucleus, but still have DNA (bacteria)
12
Q
Eukaryote
A
cells that have a nucleus containing DNA
13
Q
Why are cells so small?
A
as cells grow, the volume increases faster than the surface area if cells were larger: -nutrients cannot enter fast enough -wastes cannot leave fast enough *cell poisons itself*
14
Q
The 3 main regions of the cell
A
- cell membrane
- nucleus
- cytoplasm
15
Q
The Cell Membrane (plasma membrane)
A
- boundary that gives shape and flexibility
- “selectively permeable”: chooses what to let in/out of the cell
- “fluid mosaic” by allowing lipids & proteins to move around and form pores
- allows interactions and communication with other cells
16
Q
Types of proteins embedded in the cell membrane
A
- receptors: ready to accept chemical reactions
- messengers: send messengers
- enzymes: speed up reactions
- carrier/pumps: carry substances back and forth
- (need ATP)
- channel proteins: channel material in and out of cell
- molecular motors: motor proteins help movement
- cell identity markers
- cell adhesion molecules
17
Q
The Nucleus
A
protects and contains the heredity molecule DNA
-involved in cellular control and cellular division
18
Q
The Cytoplasm
A
semifluid substance between the cell membrane and nucleus
- contains dissolved substances, organelles, and filaments of the cytoskeleton
- “cytoplasmic streaming”: constant motion
19
Q
what are the external structures of a cell
A
- glycocalyx
- microvilli
- cilia
- flagella
20
Q
glycocalyx
A
cell recognition, adhesion, fertilization, development
21
Q
microvilli
A
increases surface area of a cell
22
Q
cilia
A
cellular movement and sensations
23
Q
flagella
A
locomotion
24
Q
what are the internal structures (organelles)?
A
- nucleus
- ribosome
- smooth endoplasmic reticulum
- rough endoplasmic reticulum
- golgi body
- mitochondria
- vesicles
- cytoskeleton
- centrioles
25
nucleus
cellular control & division
26
parts of the nucleus
- nucleoplasm
- nucleolus
- nuclear envelope
- chromatin
27
nucleoplasm
a viscous fluid that fills the nucleus: where chromatin is suspended
- similar to cytosol
28
nucleolus
a dense irregular shaped region rich in proteins and nucleic acids where ribosomal subunits are made
29
nuclear envelope
```
double membrane (two lipid bilayers) that makes the outer boundary of the nucleus
- its pores and proteins allow certain substances to enter and leave the nucleus
```
30
ribosome
assemble proteins and interpret the genetic code
31
smooth ER
- produces lipids
| - breaks down carbohydrates, fatty acids, and toxins
32
rough ER
produces, modifies, and transports proteins
33
golgi body
modifies polypeptides into mature proteins
| -sorts, ships, and packaging proteins and lipids in and out of the cell
34
mitochondria
produces ATP molecules for use during cellular respiration
* have their own DNA and ribosomes, and divide independently of the cell*
* *has two membranes, one highly folded inside the other**
35
vesicles
transport and stores substances inside the cell
| *also digests worn out cell parts*
36
cytoskeleton
protein fibers that provide shape, support and movement for the cell
37
centrioles
move cellular parts during cell division; where microtubules are grown
38
How do cells communicate?
through cellular junctions
39
adhering junctions
holds cells together to each other
40
gap junctions
provide communication between cells
| *hormones and/or neurotransmitter*
41
tight junctions
prevent leakage between cells
42
the cytomembrane system
a series of organelle (ER, golgi body, and vesicles) in which lipids are made and polypeptide chains are modified into proteins to be used in the cell/out of the cell
43
plant cell differences
- cell wall
- vacuole
- plastids
44
cell wall
gives support and protection to the plant cells
45
central vacuole
stores H2O, enzymes, and waste
| **when plant is water, vacuole will fill up with water and push the organelles against the cell membrane
46
plastids
stores food and absorbs different wavelengths of light
47
chloroplast
the main plastid in plant cells
| -makes sugars (in plants and some protists)
49
chromatin
if DNA is balled up in a non-dividing cell
49
chromsome
if DNA is ready or going in to either meiosis or mitosis in a dividing cell
**chromatin turns into chromosome**
50
The Cytoskeleton
complex system of interconnected protein filaments
| - parts of the cytoskeleton reinforce , organize, and move cell structures
51
parts of the cytoskeleton
- microtubule
- microfilament
- intermediate filament
52
microtubule
long, hollow cylinders that's function is movement
- can rapidly assemble and disassemble
* *consist of subunits of the protein tubulin**
53
microfilament
fine fibers that reinforces cell membrane & connect and support the plasma membrane
- functions in cellular movement,contraction, shape changes and migration
* *consists primarily of the protein actin**
* part of the cell cortex*
54
cell cortex
region of cytoplasm just inside the plasma membrane
55
intermediate filaments
stable cytoskeletal element in animal cells (and some protists)
- lends structure and resilience to cells and tissues
* different types are assembled from different fibrous proteins*
56
extracellular matrix
a large network of proteins and other molecules that shape, support, and give structure to cells and tissues in the body
ex. plant wall
57
primary wall
thin walls containing cellulose produced by growing cells (thin walls provide flexibility as the organism grows)
- all plants have a primary cell wall
58
middle lamella
the layer that cements the primary wall to adjoining plant cells together
- all plant cells have a middle lamella
- made up mainly of pectin ( a complex set of polysaccharides)
59
secondary wall
the sturdier wall that develops in many plant cells; but not all
- only develops after primary wall is complete and organism has stopped growing
- has permanent rigidness that gives the plant support
* made up cellulose, lignin and other polysaccharides *
60
lignin
compounds most present in secondary plant walls
- gives land plants its wood texture and color
- gives plants its strength and rigidness
- protects plants from pests and pathogens
61
plasmodesmata
a channel passing through the plant wall
- allows adjacent plant cells to communicate
* similar to gap junctions in animal cells*
