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BIO 270: Chapter 2

Exam 1
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Compare prokaryotes and eukaryotes
Eukaryote: 10^14 human
Prokaryote: 10^15 bacterial
(10% human, 90% bacteria)
What are the 3 major components of cells?
1. plasma membrane
2. nucleus
3. cytoplasm
Where does transcription occur?
in nucleus
Where does translation occur?
in cytosol
What is translation?
process of converting mRNA message into polypeptide
What is transcription?
process of copying sequences of DNA to produce complementary strands of RNA
What is another name for the plasma membrane?
cell membrane
What is the function of the plasma membrane?
-controls movement of molecules into and out of the cell
-separates the ICF and ECF
-surrounds every cell
What macromolecule is the plasma membrane mostly comprised of?
lipids! studded with proteins
What is the plasma membrane?
thin membranous structure that encloses each cell
What are the 2 major components within each cell?
cytoplasm and nucleus
What is typically the largest single organized component of a cell?
nucleus
What are the 2 main functions of DNA?
1. directs protein synthesis
2. serves as genetic blueprint during cell replication
How does DNA direct protein synthesis?
-specific genetic code is transcribed into mRNA which exits nuclear pores
-within cytoplasm mRNA exits nucleus
What is cytosol?
the gel-like liquid of the cytoplasm not occupied by organelles
What is the cytoplasm?
-portion of cell interior not occupied by nucleus
-consists of organelles
What is referred to as little organs?
organelles- located in cytoplasm
What is an organelle?
distinct, highly organized, membrane-enclosed structure
List all organelles.
ER (rough, smooth), free ribosomes, golgi complex, lysosome, perioxisome, cytoskeleton, mitochondria
What is also referred to as the cell's highway?
endoplasmic reticulum
Describe the rough ER
-surface has attached ribosomes
-protein synthesis occurs(translation)
Where is the RER most abundant?
in cells specializing in protein synthesis- (pancreas)
Describe the smooth ER
-no ribosomes, not involved in protein synthesis
-formation of transport vesicles
-lipid synthesis (cholesterol, steroids, hormones)
-in liver
What structure produces transport vesicles and what organelle do they go to next?
smooth ER, go to golgi complex
What is a major function of the smooth ER?
lipid synthesis, also have enzymes that detoxify harmful compounds
Would an alcoholic have more or less SER?
more- need more to break down all the alcoholic toxins
(positive feedback)
What is the name of the process that creates mRNA?
transcription- process occurs in the nucleus
What is the name for protein synthesis in ribosomes?
translation
What organelle is closely related with the ER?
golgi complex
What are the main functions of the golgi complex?
-process raw materials made by ribosomes
-sort and direct products to their final destination
Describe the golgi complex
stack of flattened, slightly curved, membrane-enclosed sacs (cistern)
What are the sacs in the golgi complex called?
cisternae
What do lysosomes contain?
lytic or hydrolytic (digestive) enzymes
What is the function of lysosomes?
-help digest worn out organelles
-recycle components (building blocks) or macromolecules
-importnat to immune system
How does bacteria move through the cell?
thermal energy
What is the function of hydrolytic enzymes?
add water to molecule and it breaks the cell
What are the 3 types of endocytosis?
1. pinocytosis
2. phagocytosis
3. receptor mediated endocytosis
Describe phagocytosis
(cell-eating) large multi molecular particles are internalized- only done by specialized cells
What organelle releases secretory vesicles?
golgi complex- exit cell through exocytosis
What is secretion?
refers to release to cells exterior on appropriate stimulation
What is the primary mechanism for accomplishing secretion?
exocytosis
What type of endocytosis is used in white blood cells?
phagocytosis
Describe pinocytosis
(cell drinking) droplet of ECF is taken up non selectively
(removes added plasma membrane brought by exocytosis)
Describe receptor mediated endocytosis
highly selective process that enables cells to import specific large molecules (coated pits)
What is the function of peroxisomes?
membrane organelle that produces and decompose hydrogen peroxide- detoxify various waste products
What organelles do peroxisomes come from?
ER and golgi complex
What organelle contains oxidative enzymes?
peroxisomes
What is used to breakdown hydrogen peroxide in peroxisomes?
catalase
What organelle is known to provide energy?
mitochondria- major production site for ATP
What are the 3 processes that produce ATP in mitochondria?
glycolysis, citric acid cycle (krebs cycle), oxidation phosphorylation
Describe the mitochondrial matrix
gel-like solution in inner cavity; contains hundreds of enzymes
Name two important traits of mitochondrial anatomy
1. has its own DNA
2. consists of 2 membranes
What is metabolism?
sum total of endergonic (energy needed for reaction) and exergonic (energy released by reaction) reactions carrier out by cell
Define catabolism
breaking down of cell components
Define anabolism
synthesis of new proteins or components
Where is energy first stored?
in fooood!
What type of macromolecules have high energy electron content in covalent bonds?
carbohydrates and lipids
What is the difference between oxidation and reduction?
oxidation: add oxygen to molecule, remove electron
reduction: remove oxygen, add electron
True or false. The transfer of high energy electrons from food releases energy which is stored as ATP
TRUE
Is ATP produced directly by the citric acid cycle?
NO
What is the equation that forms ATP?
ADP+GTP->ATP+GDP
What is each glucose converted into during glycolysis?
acetyl-CoA
Where does glycolysis take place?
cytosol
Where does the citric acid cycle take place?
mitochondrial matrix
Where does oxidation phosphorylation take place?
mitochondrial inner membrane
What are the 3 steps of cellular respiration?
glycolysis, citric acid cycle, and oxidation phosphorylation
What 2 groups of proteins are involved in oxidation phosphorylation?
ATP synthase (chemiosmosis) and electron transport system
Describe the electron transport system
electrons flow through a series of electron carriers from high-energy to low energy levels; energy released builds a H+ gradient across the inner mitochondrial membrane
Describe chemiosmosis
ATP synthase catalyzes ATP synthesis using energy from the H+ gradient across the membrane
What happens to glucose during glycolysis?
it is oxidized and NAD and FAD are reduced to NADH and FADH2
Where do protons travel during the electron transport system?
from the mitochondrial matrix to the inter membrane space of the mitochondria
How do protons travel back from the inter membrane space to the mitochondrial matrix?
through ATP synthase- energy is derived from this movement- synthesizing ATP from ADP and phosphate
Why is energy released as heat?
-heat eliminated to environment
-maintain body temperature
What is produced in the cellular respiration equation?
6CO2+6H20+32-36 ATP+ heat
Which step in cellular respiration is anaerobic?
glycolysis
What is produced with one turn of the krebs cycle?
3 NADH and 1 FADH2
How many pyruvate are produced from 1 glucose?
2
how many pyruvate are required for 2 turns of the krebs cycle?
2
What does anaerobic mean?
no oxygen required
Describe glycolysis
chemical process involving 10 separate reactions that breakdown glucose into 2 pyruvate molecules
What happens to the pyruvate group in the citric acid cycle?
converted into acetyl CoA
What step in cellular respiration is important to preparing carrier molecules to electron transport system
NADH and FADH- carry protons
Describe the citric acid cycle
consists of 8 biochemical reactions that are directed by enzymes located in the mitochondria
Where exactly is the electron transport chain located?
on cristae of the inner mitochondria membrane
In aerobic conditions how many ATP are produced?
32 (2 from glycolysis which can occur in anaerobic conditions also)
What process cases fatty acids to be broken down in the mitochondrial matrix?
beta oxidation
What happens after glycolysis under anaerobic conditions?
lactate build up
What are the 3 elements of the cytoskeleton?
1. microfilaments
2. micotubules
3. intermediate filaments
Define apoptosis
deliberate cell suicide cause be mitochondria
What role do ribosomes have in carrying out protein synthesis?
translating mRNA into chains of amino acids in the ordered sequence dictated by the original DNA code
What occupies 55% of total cell volume?
cytosol
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