bio test 2 Flashcards
(72 cards)
1
Q
cell
A
- fundamental structural and functional unit of an organism/living thing - capable of performing all the necessary functions of life
- very small; many are only as small as 1/1000 mm (1 micrometer)
2
Q
surface area to volume ratio
A
- the smaller the cell is, the larger its SA2VR is
- makes cell more efficient in absorption and excretion at the cell’s surface
- many cells increase their SA2VR by having finger-like projections (brush border)
3
Q
3 examples of finger-like projections
A
- villi in small intestine have many tiny projections called microvilli which increase efficiency of absorption of nutrients
- PCT (proximal convoluted tubule) of a nephron in the kidney has microvilli for efficient absorption
- alveoli in lungs are very small to increase SA2VR for efficient diffusion of oxygen into carbon dioxide out of blood/lungs
4
Q
organelles
A
- almost all human cells have these in common
- perform specific tasks/functions
5
Q
nucleus
A
- controls all cell activities through genes on DNA such as protein synthesis, cell division and all other metabolic functions
6
Q
chromatin and chromosomes
A
- made up of DNA and proteins such as histones
- chromatin is seen as a network of fibrils when cell is not dividing. during cell division, distinctly shaped chromosomes are seen
- human cells normally have 23 pairs of chromosomes
7
Q
nucleoplasm
A
- semifluid. liquid found in nucleus, rich in enzymes and many monomers like nucleotides
- nucleoplasm has slightly different pH and composition than cytoplasm
8
Q
nuclear envelope/membrane
A
- double membrane which separates nucleus from cytoplasm
- similar to cell membrane but lacks recognition chains found on surface of cell membrane
9
Q
nuclear pores/holes
A
- nuclear membrane has tiny pores through which info and materials pass between nucleus and cytoplasm
- ex/ RNA synthesized in nucleus passes through pores for cytoplasm and some proteins produced in cytoplasm are imported
10
Q
nucleolus
A
- 1 or more dark area inside nucleus
- produces rRNA (ribosomal RNA). rRNA is the major component of ribosomes (ribosome = rRNA + proteins)
11
Q
rough endoplasmic reticulum (RER) location
A
- typically RER are attached to nuclear envelope
- abundance of RER found where proteins/enzymes are synthesized such as liver and pancreas cells
12
Q
translation in RER
A
- individual amino acids are brought to ribosomes attached to ER and joined together by peptide bonds. result is linear structure of protein which enters lumen/ cavity of RER.
13
Q
final protein shape given in RER
A
- hydrogen bonds between amino acids form resulting in secondary structure. ionic bonding between R-groups of amino acids/disulphide bonding gives the protein its tertiary structure. for some proteins such as myosin, the 3D shape is final. other proteins like oxygen carrying protein in red blood cell, Hb, moves on to 4th stage where several proteins join together to work as team
14
Q
carb chain/metals/ minerals and other specific components attached in RER
A
- functional proteins are rarely 100% amino acids. they have carb chains attached to them. these proteins are known as glycol (sugar) proteins like the ones present on surface of plasma membrane
- metals such as iron are present in Hb. attachment of iron in Hb is done in RER.
15
Q
rigorous quality control of freshly prepared proteins maintained in RER
A
- incorrectly formed or folded, or proteins with errors during synthesis are rejected by RER. rejected polypeptides are stored in lumen or sent out for recycling.
16
Q
emphysema
A
this lung disease occurs when a faulty gene makes wrong folding of protein. protein is assembled as usual but due to wrong folding, RER quality control rejects it and it never reaches its destination
17
Q
cystic fibrosis and RER quality control
A
- occurs when a single amino acid, phenylalanine, is missed at a particular position during translation/putting amino acids together by a faulty gene. RER finds error and rejects the required protein causing complications like irregularities in chloride ion transport and accumulation of mucus
18
Q
smooth endoplasmic reticulum (SER)
A
- not studded with ribosomes; smooth in texture
- abundance found in liver where detox of drugs happens (liver is known as gate keeper. everything that enters blood /body will pass through liver), in testis and ovaries where steroid hormones are made, and in cells which make lipids and phospholipids.
19
Q
main functions of SER
A
- transport products of RER to Golgi bodies (packaged into transport vesicles)
- synthesis of oils such as skin oils and skin glands
- synthesis of phospholipids for plasma membrane
- synthesis of steroids and cholesterol
- detoxification of drugs and alcohol (their byproducts are poisonous for cells)
20
Q
ribosomes
A
- made up of 2 subunits and consist of rRNA + proteins
- proteins are assembled here from amino acids
- only known organelles in cells which lack plasma membrane
21
Q
smaller subunit of ribosome, larger
A
- s: binding site for mRNA (messenger RNA)
- l: completes the ribosome
22
Q
3 types of ribosomes
A
- free ribosome
- polysomes/polyribosomes
- ribosomes attached to ER/ on RER
23
Q
Golgi bodies/apparatus
A
- continues function of processing, modification, and attaching destination tags. after products leave the ERs, Golgi gives finishing touches and packages them into secretory vesicles
- Golgi and RER attach destination tags so that they would go where they are meant for
24
Q
lysosomes
A
- one of the many types of products which are given final touches by the Golgi for cell’s internal use
- “garbage disposal units” “suicide sacs”
- tiny vesicles which contain hydrolytic enzymes for cell’s internal use. enzymes break apart unwanted polymers by the process of hydrolysis
25
where may products of ERs be used?
- for internal use or to export to other cells. if for export, they are sent to cell membrane and exported to other cells by a process called exocytotis
26
functions of lysosomes
- auto digestion (old/nonfunctional cell parts are broken down and recycled)
- breaking down bacteria and viruses which invade cells
- destroying cells which could become cancerous
- when cell itself becomes "too old" and not as useful, cell commits suicide using hydrolytic enzymes
27
abundance of lysosomes and Golgi are found in...
- Golgi is abundant in cell's synthesizing products (liver, pancreas)
- lysosomes abundant in cells which fight infections (white blood cells or WBCs)
28
mitochondrion is bound by a ___
double membrane. inner membrane invaginates (folds inwards) finger- like projections known as cristae
29
cristae
provides a large surface area for the biochemical reactions inside the mitochondrion. Many reactions such as the ‘electron transport chain’ take place at crista during the formation of ATP
30
the inner space of the mitochondrion is known as the ___
matrix. It is filled with a gel-like fluid that is rich in monomers, proteins and enzymes etc. Many reactions such as the ‘preparatory reactions’ and the ‘citric acid cycle reactions’ take place in the matrix during ATP production
31
are some proteins made at mitochondrial ribosomes?
yuh
32
mtDNA
- mitochondrial DNA
- mtDNA in a fertilized egg comes from mom. father’s mitochondria are concentrated in the sperm’s tail and left outside of the egg during fertilization. egg’s plasma membrane enzymes destroy any mitochondria from sperm.
- studies trace ‘maternal linage’ of humans far back. ‘Mitochondrial Eve’ is underway to find out origin of humans by tracking lineage based on mtDNA
- also used in forensic sciences
33
mitochondria are the ___ of the cell
powerhouse
- They produce almost all of the energy/ATP required by the cell
- The cell’s ‘energy currency’ is ATP; adenosine triphosphate
- needed whenever energy is required
34
ADP
adenosine diphosphate. "low energy" ATP
35
cellular respiration
- process of making ATP
- The biochemical reactions involved in making of ATP add up to the following equation: C6H12O6 + 6O2=>36-38 ATP + 6CO2 +6H2O
36
ATP are known as
active/active transport
37
exocytosis
- active transport
| - involves transporting out of cell using ATP (ex/ digestive enzymes, hormones, neurotransmitters)
38
endocytosis
- active transport
| - involves transporting into the cell using ATP (ex/ WBC engulf bacteria by endocytosis)
39
abundance of mitochondria
- found in every cell. Are abundant/found largely in active cells such as heart cells, PCT (proximal convoluted tubules) of kidney, mid piece and tail of sperm, microvilli of small intestine
40
cytoskeleton
- cell’s 'skeleton’ contained in cytoplasm
- maintains cell’s shape, gives it strength and allows the cell and its organelles to move
- contains actin filaments, intermediate filaments and microtubules
41
actin filaments
- longest, thinnest and most flexible fibres such as
the ones present in microvilli of small intestine and the ones that form a dense complex web under plasma/ cell membrane to give it strength
42
intermediate filaments
- ropelike assembly of fibrous polypeptides such as
the ones present at nuclear membrane and plasma membrane to provide support. In skin and human hair they give great mechanical strength to the cells
43
microtubules
- help maintain cell shape and allow intracellular transport( within the cell) such as helping in the movement of vesicles and organelles e.g mitochondria on/ along them
- form cilia and flagella eg. cilia is found inside trachea which sweep the debris-trapping mucus away from lungs to clean the inhaled air
- sperm tail consists flagellum, helps sperm swim/move
44
chloroplast in plant cell
- Found in plants and algae, double membrane
- Uses sun’s energy to produce carbohydrates and oxygen
- photosynthesis: CO2 + H2O + solar energy => carbohydrates + O2
- Carbohydrates ( polymers) are broken down into glucose and other monosaccharides by digestive system
- Glucose obtained from digestive system and oxygen are involved in cellular respiration mainly in mitochondria to produce ATP
45
production and secretion of cell's products
DNA contains protein codes. Assembly of amino acids is on ribosomes (RER) in cytoplasm. DNA doesn't leave nucleus; copies code onto messenger RNA (mRNA). mRNA gives ribosome message, then amino acids get peptide bonded. new polypeptide (protein) enters lumen (cavity) of RER for processing. polypeptide goes to SER for packaging into transport vesicles. these travel to Golgi bodies for processing and final packaging into secretory vesicles. if for export, vesicles fuse w/plasma membrane and release products outside cell into tissue fluid by exocytosis
46
secretory vesicles may contain products ___
- For cell’s internal use such as lysosomes and phospholipids for cell membrane.
- For exports to other cells.
47
the mitochondria is abundant in cells involved in a) active transport b )diffusion of oxygen c) osmosis d) transport of lipid-soluble molecules
a) active transport
48
what could be produced by the cell with a large amount of SER? a) enzymes b) antibodies c) hemoglobin d) testosterone
d) testosterone
49
which structure stores genetic info?
nucleolus
50
RER is composed of molecules produced by the ___
nucleolus
51
consider DNA, pepsin, maltose and water molecules. how many of these substances have hydrogen bonding?
3 (DNA, pepsin and water)
52
which of the following is packaged and stored by the Golgi bodies? a) water b) enzymes c) carbon dioxide d) messenger RNA
b) enzymes
53
which of the following is produced by the Golgi bodies? a) lysosomes b) transport vesicles c) RNA d) polypeptides
a) lysosomes
54
consider the following molecules: glycogen, testosterone, phospholipids, amylase, DNA polymerase. how many of these are produced at ribosomes?
2 (amylase and DNA polymerase)
55
one function of a ribosome is to a)replicate DNA b) produce amylase c) transcribe mRNA d) hydrolyze nucleus
b) produce amylase
56
in which of the following is the greatest amount of DNA found? a) nucleus b) ribosome c) nucleolus d) nuclear envelope
c) nucleolus
57
an organelle composed of a stack of flattened saccule may function to a) propel the cell b) replicate DNA c) produce glucose d) package proteins
d) package proteins
58
which of the following is a function of vacuoles in the animal cell? a) store substances b) digest cell parts c) synthesize proteins d) fuse with ER
a) store substances
59
vacuole
- large membranous sac
- prominent in plant cells and adds support to these cells
- plant vacuoles store substances such as pigments and toxic molecules (to protect against herbivores)
60
do proteins have hydrogen bonding?
yes, in secondary structure
61
do disaccharides have hydrogen bonding?
no
62
where is abundance of ribosomes
- wherever proteins/enzymes are synthesized, like in liver, pancreas, etc
63
main functions of RER
translation, final shape of protein is given, carbs/chain/ metals/minerals, etc are attached, rigorous quality control of freshly prepared proteins is maintained
64
which 2 organelles are responsible for endocytosis
the mitochondria and the cell membrane
65
what contains the most amount of DNA?
the nucleolus
66
which type of organelle forms a membranous system of tubular canals, which is continuous with the nuclear envelope and branches throughout the cytoplasm?
ER
67
which organelle contains enzymes that modify proteins and lipids?
Golgi apparatus
68
which organelle synthesizes proteins for export or repackaging elsewhere?
RER
69
which plant organelle will provide added support to the cell?
vacuole
70
which organelle is used when the fingers of a human embryo are at first webbed but later freed from one another?
lysosomes
71
mRNA
- acts as messenger between DNA and protein production
| - serves as genetic template since DNA can't leave nucleus
72
tRNA
- (transfer RNA) responsible for bringing amino acids together during translation to form the growing peptide shape
