Exam 2 Flashcards
1
Q
cells
A
basic structural and functional unit of life
2
Q
4 basic features common to ALL cells (Prokaryotic and Eukaryotic)
A
- Plasma
- DNA
- Cytoplasm
- Ribosomes
3
Q
All Eukaryotic cells:
A
- Nucleus
- membrane bound organelles (Mitochondria, Golgi bodies, ER)
Examples: Protists, fungi, animals, plants
4
Q
All Prokaryotic cells:
A
- lack a nucleus
- have DNA in an unbound region called NUCLEOID
- NO membrane-bound organelles
Examples: Bacteria, Archaea
5
Q
Nucleus
A
Contain most of the cell’s DAN and is enclosed by a nuclear envelope, separating it from the cytoplasm
6
Q
nuclear envelope
A
double membrane, each membrane consists of a lip bilayer
7
Q
Chromatin
A
DNA and proteins form this genetic material in the nucleus
8
Q
ribosomes
A
particles made of ribosomal RNA and protein
9
Q
Ribosomes carry out protein synthesis in what two locations?
A
- Cytosol (free ribosomes)
2. on the outside of the ER or the nuclear envelope (bound ribosomes)
10
Q
ER exists in two forms:
A
- rough ER
2. Smooth ER
11
Q
Rough ER
A
ribosomes studded on its surface
12
Q
smooth ER
A
Lack of ribosomes on its surface
13
Q
Golgi apparatus
A
where the processing and packaging of molecules that were made in the ER takes place
14
Q
Functions of the Golgi apparatus:
A
- Modifying products of the ER
- making certain macromolecules
- sorting and packaging materials into transport vesicles
15
Q
central vacuole
A
biggest organelle found inside mature plants, taking up as much as 80% of the volume
16
Q
functions of the central vacuole
A
- storage of water and organic compounds
- a compartment for waste disposal
- pigments to attract pollinators
- toxins to deter Herbivores
17
Q
plasma membrane
A
selective barrier that allows passage of oxygen and nutrients into the cell and of water material out of the cell
- doesn’t allow every kind of molecule to pass through but only a selective few
- composed of a double layer of phospholipids
18
Q
mitochondria
A
- organelle where respiration takes place
- has smooth outer membrane and inner folded membrane
19
Q
cristae
A
ridges, that present a large surface area for enzymes that synthesize ATP in the mitochondria
20
Q
ATP
A
adenosine Triphosphate serves as an energy molecule, since it has the potential to react with water and release energy stored In its bonds
21
Q
chloroplasts
A
- site of photosynthesis
- contain green chlorophyll and other molecules that function in photosynthesis
- found in leaves and other green orgs of plants and in algae
22
Q
three out important components of chloroplast
A
- thylakoids
- geranium
- stroma
23
Q
thylakoids
A
membrane sacs in chloroplasts
24
Q
geranium
A
stacked up thylakoids in chloroplasts
25
stroma
fluid inside chloroplasts
26
cytoskeleton
network of fibers found in the cytoplasm of a cell
27
three main types of cytoskeleton
1. microtubules (thickest of the three)
2. microfilaments (thinnest components)
3. intermediant filaments (fibers in the middle range)
28
main functions of a cytoskeleton:
1. support and maintain cells shape
2. anchoring organelles
3. helping chromosome movement during cell division
4. cell motility (locomotion via structures like cilia and flagella)
29
3 types of extracellular structures
1. cell walls of plants
2. the extracellular matrix (ECM) of an animal cell
2. intercellular junctions in. both plants and animals
30
extracellular structures
the structures found outside the cells serve various functions such as:
1. protection
2. communication between cells
3. transport of substances in and out of cell
31
cell wall
- an extracellular structure that is found in plants, algae, fungi, and most bacteria however is absent in animals
- protects the plant cells, maintains its shape and prevents excessive uptake of water
- `made of cellulose fibers embedded in other polysaccharides and protein
32
ECM (extracellular matrix)
- animals cells lack a cell wall but are covered in this
- made up of glycoproteins
- functions
1. support the cells structure
2. cell to cell adhesion
3. movement of substance across cell
4. regulate intercellular communication
33
4 main types of intercellular junctions
1. tight junctions (formed from cells pressing together, prevents leakage of external fluid). found in the stomach lining to prevent the stomach acid from seeping into the stomach
2. desmosomes (fasten cells together by interlocking joints. found in skin to resist tear and strain)
3. gap junctions (communication channels in an animal cell for the movement of water and solutes between adjacent cell)
4. plasmodesmata (communication channels in plant cells for movement of water and solutes between adjacent cells
34
DNA
- a nucleic acid
- stores and transmits hereditary information
- what genes are made of
- directs synthesis of messenger RNA (mRNA) and through mRNA controls protein synthesis
35
protein syntesis occurs in...
ribosomes
36
nucleic acids are polymers called...
polynucleotides
37
each polynucleotide is made of monomers called...
nucleotides
38
each nucleotide consists of...
1. Nitrogen base (A,G,T,C or U)
2. a pentose sugar (deoxyribose- found only in DNA or ribose- found only in RNA)
3. a phosphate group (PO4)
39
5 nitrogenous bases
1. adenine
2. Guanine
3. Cytosine
4. Thymine (only in DNA)
5. Uracil (only in RNA)q
40
DNA has two polynucleotides spiraling around forming a...
double helix
41
The nitrogenous bases in DNA always pair as the following:
A with T
T with A
G with C
C with G
42
true or false:
| The information in DNA is in the form of specific sequences of nucleotides
true
43
Gene expression
The process by which DNA makes mRNA (by transcription) and mRNA makes Protein (by translation)
44
true or false: the sequences of bases alone a DNA or mRNA polymer is unique for each gene
true
45
true or false:
| RNA is the intermediate between DNA and the proteins for which they code
true
46
transcription
makes messenger RNA from DNA
this mRNA carries the message or how to make a protein from the RNA
47
translation
the synthesis of a protein or polypeptide from the mRNA
48
RNA is catalyzed by an enzyme called...
RNA Polymerase
49
in RNA, Uracil substitutes for _______ in DNA
thymine
50
initiation
the RNA polymerase bind to. promoter region on DNA & initiate the process of transcription
51
elongation
transcription stops when the polymerase reaches the end of transcription unit
52
Codon
flow of information from DNA to protein is based on an intermediate mRNA TRIPLET CODE
53
true or false:
| a Condon is an mRNA based triplet formed after Transcription if DNA (AAG,UAA,AGU)
true
54
how many codons code for amino acids
61
55
name the 1 amino acid start codon, required to start the translation process
AUG
56
during translation, these mRNA based triplet, called codons are ______ by _______
read, ribosomes
57
each codon specifies the addition of one of ___ amino acids
20
58
initiation
begins at start codon AUG
59
elongation
during this stage each codon read by ribosome bring in an amino acid
60
termination
this occurs when stop codon in the mRNA reaches thee ribosome
61
eukaryotic cell cycle
1. interphase
| 2. mitotic
62
interphase
cell growth and replication phase
G1, S, G2
63
mitotic phase
cell division phase
mitosis, cytokinesis
64
cell cycle control system
whether a cell goes through the G1, S,m G2 and M phase of a cell cycle or not is controlled by this
also regulated by both internal and external signals
65
checkpoints
determines whether the cell is ready to go through the next phase of the cell cycle or not
G1 (most important) -> if it receives the go ahead then it goes into the S phase and undergoes replication (synthesis) of DNA, -> IF the cell does not get the go ahead then it will exit the cycle and enter into a nondividing (quiescent) state called G0 (cell arresting itself), G2, M
66
Cyclin-CDK complexes
act as an internal signal to the cell
their presence makes the cell go to the next phase
if these do not form the cells arrest themselves and do not go into the next phase
67
external signals
1. growth factors
- stimulates the cells to grow and signal them to go to the next phase and eventually divide
- the absence serve as the signal to seize growth and division
2. density-dependent inhibition
- absence of this signals the cells to continue dividing
- when overcrowding begins the cells pick up that signal and stop dividing
3. anchorage dependence
- need for cells to have a medium or surface to attach to in order to grow
68
loss of cell cycle control system
- when a cell goes through the phases despite receiving a stop signal
- seen in cancer cells
69
transformation
how normal cells are converted to cancerous cells which form masses called tumors
70
benign tumor
if abnormal cells remain at there original site the lump is called this
71
malignant tumor
if abnormal cells leave the original site and start invading surrounding tissues, it is called this
72
metastasis
when the malignant tumor continues to grow and spreads to the rest of the body using blood or lymph as a medium forming SECONDARY TUMORS at these new locations
73
cancer related deaths
1. Lung cancer
2. colon cancer
3. breast cancer
74
cell cycle
the life of a cell from formation to its own division
75
the continuity of life is based on the reproduction of cells or _________
cell division
76
cell division =
nucleus division + cytoplasm division
77
nucleus division
mitosis or meiosis (depends on type or cell undergoing division)
78
cytoplasm division
cytokinesis
79
genome
all the DNA in a cell constitutes the cells _____
80
DNA molecules in a cell packed with proteins make up _______
chromatin (during cell division comes together and condenses into structures called chromosomes)
81
humans have how many chromosomes
46
82
diploid cell (2n)
two sets of chromosomes (humans = 46)
83
haploid (n)
gamete (sperm and egg) contain a single set of chromosomes (humans = 23)
84
somatic cell
all body cells except sex cells (all diploid)
85
germ cells
diploid cells found only in gonads (testis and ovary)
86
zygote
diploid cells fired from fertilization of sperm and egg (one set of chromosomes from each parent)
87
fertilization
union of gametes
88
mitosis
-zygote produces somatic cells
- phases
1. prophase
(chromosomes first become visible, chromatin condenses into tightly packed structures called chromosomes)
2. pro metaphase
3. metaphase
(chromosomes line up in the middle)
4. anaphase
(sister chromatids separate and move towards opposite ends of the pole)
5. telophase
(cytokinesis is underway by late telophase)
(genetically identical daughter nuclei are at the opposite ends of the cell and the nuclear division is complete)
89
meiosis
gametes are produced but this
stages
- meiosis I
- prophase I
- metaphase I
- anaphase I
- telophase I and cytokinesis
- meiosis II
- prophase II
- metaphase II
- anaphase II
- telophase II and cytokinesis
90
crossing over
contributes to genetic variation
91
recombinant chromosomes
combine genes inherited from each parent
92
sister chromatids
pair of chromosomes (non identical)
93
living organisms are distinguished by...
their ability to reproduce their own kind
94
genes
units of heredity and are made up of segments of DNA
also passed on through gametes
95
at the end of meiosis their are ____ daughter cells
4
96
what is responsible for most of the genetic variation and how does it occur?
meiosis
1. independent assortment of chromosomes
2. crossing over
97
independent assortment of chromosomes
each pair of chromosomes sorts its self independently of other pairs
