Cell Biology Flashcards
four classes ofa organic molecules
Lipids, carbohydrates, proteins, nucleic acids
Monosaccharide
Single sugar molecule
Examples of monosaccharides
Glucose, fructose, galactose
Number of carbons in glucose and fructose
6
Disaccharide
Two sugar molecules joined by a glycosidic linkage
Examples of disaccharides
Lactose, sucrose, maltose
Polysaccharides
Series of connected sugar molecules
Function of starch
Energy storage in plant cels
Function of glycogen
Energy storage in animal cells
Cellulose
Structural support in plant cells
Chitin
Structural in walls of fungus and arthropod exoskeletons
Lipids
Hydrophobic molecules
Functions of lipids
Insulation, energy storage, structural, endocrine
Triglycerides are found in ___
fats and oils
Triglycerides are composed of
A glycerol molecule connected to three fatty acid tails
Saturated triglycerides
No double bonds in fatty acid tails
Monounsaturated triglycerides
One double bond in fatty acid tail
Polyunsaturated triglycerides
two or more double bonds in fatty acid tail
Structure of phospholipids
Glycerol group and phosphate group. Two fatty acid tails
Amphipathic phospholipids
Fatty acid tails are non polar hydrophobic and glycerol and phosphate are polar hydrophilic
Function of phospholipids
Forms cell membrane
Glycolipids
Phospholipid but contains carbohydrate instead of phosphate group
Steroid Structure
Backbone of four linked carbon rings
Proteins
Polymers of covalently bonded amino acids
Structure of amino acid
Central carbon with an amino (NH3), carboxyl (COOH), hydrogen (H), and (R) group
What does peptide bond formation produce?
Water
Types of proteins
Storage, transport, defensive, enzymes
Primary protein structure
Amino acid sequence
Secondary Protein structure
Localized folds due to hydrogen bonding
Tertiary protein structure
Overall 3D shape of protein due to interactions within protein
Quaternary protein structure
2 or more peptide chains coming together by protein bonding. Not present in all proteins.
Protein denaturation
Structures above secondary protein structure are removed from the protein. Protein is not broken down into individual amino acids.
Nucleotides
Phosphate group, sugar, and nitrogenous base
Nucleoside
Sugar and nitrogenous base
Purines
Adenine, Guanine
Pyrimidines
Cytosine, Uracil*, Thymine
Dogma of genetics
Dna to Rna to Protein
Endosymbiont Theory
Mitochondria and chloroplasts were independent prokaryotes who were engulfed by a larger cell, forming eukaryotic cells
Prokaryotic Cells
Unicellular cells with small ribosomes and no cytoskeleton. No internal membranes or organelles. Nucleoside region. Single circular chromosome. Plasmid can be present.
Photoautrotrophs
Use photosynthesis to make their food from sunlight
Chemoautotrophs
Use chemosynthesis to make food from inorganic molecules (H2S, NH3, etc.)
Heterotrophs
Obtain energy by consuming either autotrophs or products made by autotrophs
Obligate Anaerobe
Survives only when NO OXYGEN is present
Obligate Aerobe
Needs oxygen
Facultative Anaerobe
In absence of oxygen, can switch from aerobe to anaerobe
Nucleus
Contains chromosomes wrapped into histones. Surrounding by semi-permeable nuclear membrane.
Nucleolus
Site of ribosome formation
Ribosome
“Protein factories”
Two locations ribosomes can be found?
Rough ER, free-floating in cytoplasm
Ribosomes on rough ER create proteins that ____
Are destined to leave the cell
Ribosomes free-floating in cytoplasm create proteins that ____
Stay in the cell
Rough ER
Contains ribosomes that function in protein synthesis
Smooth Er
Synthesizes steroid hormones and lipids. Stores calcium in muscle cells for contraction. Detox.
Golgi Apparatus
Packages products from rough ER and sends them to their destination
Lysosomes
Sacs that contain enzymes for digestion
Mitochondria
Makes ATP. HAs own DNA and ribosomes
Peroxisomes
Detox by turning H2O2 into H2O
Cell wall
Structural support in plants and fungi. ANIMALS DONT HAVE THESE
Extracellular Matrix
Area between adjacent cells filled with fibrous structural proteins. Provides support and helps bind adjacent cells
Plastids
Contain chloroplasts and leucoplasts in plants
Cytoskeleton only in _____ cells
Eukaryotic
Microtubules
Made of tubulin. Forms spindle fibres during cell division. Found in flagella and cilia.
Microfilaments
Made of actin. Cell motility.
Intermediate filaments
Structural support for cells
Cell membrane
Semi permeable membrane that surrounds the cell. Double phospholipid bilayer. Contains cholesterol for support.
Active Transport requires ____
ATP
Types of endocytosis
Phagocytosis (cell-eating) Pinocytosis (cell-drinking) Receptor Mediated Endocytosis (form of pinocytosis where specific fluid molecules bind to receptors)
Passive Transport
Molecules move down concentration gradient without the need for ATP
Facilitated Diffusion
Movement of solutes or water through hydrophilic protein channel
Osmosis
Diffusion involving water
Plasmolysis
The collapse of a cell as a result of too much water exiting it
Dialysis
Diffusion of solutes across a selective membrane
Bulk Flow
Movement of a fluid in one direction in an organism (example: blood moving through humans)
Anchoring Junctions (Desmosomes)
Anchor cells to each other
Tight Junctions
Seal. Prevent things passing from cell to cell.
Gap junctions
Allows ions and small molecules to move between cells
Plasmodesmata
Gap junctions in plant cells
Qurom Sensing
Bacteria secrete communication molecules
Gap Junction / Plasmodesmata signalling
Direct molecule transfer between cells
Paracrine Signals
Localized signals released as growth factors
Endocrine signals
Long distance
G1 Interphase
Growth
S Interphase
growth and DNA duplication
G2 interphase
Prepare to divide
Events of prophase of mitosis
Nuclear envelope disappears. Chromatin condenses into chromosomes. Mitotic spindle is formed.
Events of metaphase of mitosis
Chromosomes align on metaphase plate. Chromosomes are attached to spindle fibres.
Events of anaphase of mitosis
Chromosomes pulled apart into sister chromatids
Events of telophase of mitosis
Chromosomes decondense. Nuclear envelope reforms.
Events of cytokinesis mitosis
Cell plate (plants) or cleavage furrow (animals) is formed, splitting the cell in two
Events of prophase meiosis
Chromatin decondenses, spindle develops, nuclear envelop disappears. Synapsis occurs (pairing of homologous chromosomes) Crossing over occurs
Events of metaphase I meiosis
tetrads align on metaphase plate
Events of anaphase I meiosis
Tetrads pulled apart
Events of telophase I meiosis
Nuclear envelope reforms.
G1 Checkpoint
Can division be undertaken?
G2 Checkpoint
Was DNA replicated succesfully?
M checkpoint
Are all chromosomes attached to spindle fibers during metaphase?
G0 phase
Cell does not divide due to being rejected at G1 checkpoint
Density dependent inhibition cell division
If area around cell is too dense, division ceases
Enzymes
Lower a reaction’s activation energy. Doesn’t change energy absorbed or released during a process.
Effect of high temperatures on enzymes
Denaturation
Effect of extreme pH on enzymes
Denaturation
Allosteric Regulation
regulation of an enzyme by a binding molecule at a site other than the enzyme’s active site
Allosteric Enzymes
HAve both a site for allosteric binding and an active site
Feedback inhibition
End product of reaction inhibits and disables enzyme
Competitive Inhibition
A substance can mic substrate and enter the active site
Non-competitive Inhibition
A substance binds to a point on the enzyme that warps its shape and disables it
Cooperativity
When one substrate binds to enzyme, its affinity for other substrates increases
Entropy
Degree of disorder in a system. Entropy of universe always increasing
First Law of Thermodynamics
Energy can’t be created or destroyed. Can only be transferred.
Second Law of Thermodynamics
All energy transfer increases the entropy of the universe
Order of appearance of life
Inorganic molecules, small organic molecules, proteinoids, protocells, heterotrophs, autotrophs, eukaryotes
Where does glycolysis occur?
Cytosol
Where does the conversion of pyruvate to acetyl coA occur?
Cytosol
Where does Krebs cycle occur?
Mictochondria
Where does electron transport chain occur?
Mitochondria
What is glycolysis converted to in the first step of glycolysis.
PGAL
In glycolysis, once glucose produces?
2 pyruvate, 1 NADH, 4 ATP
What happens after glycolysis?
Pyruvate becomes acetyl coA
What happens after acetyl coA is formed
Krebs
What is produced for every acetyl coA that enters the Krebs cycle?
3 NADH, 1 FADH2, 2 CO2, 1 GTP
What is produced for every two turns of the KRebs cycle?
6 NADH, 2 FADH2, 4 CO2, 2 GTP
What is the final electron acceptor in the ETC?
Oxygen
What does the acceptance of electrons by oxygen form?
Water
What is the ATP generating turbine?
ATP synthase
How does the ATP generating turbine turn?
Uses energy from H+ gradient
Gluconeogenesis
Generation of glucose form non-carbohydrate substances. Happens in liver and kidney
Fermentation . What happens?
Occurs anaerobically. Pyruvate becomes acetaldehyde which becomes ethanol, meaning that NADH can become NAD+
Lactic Acid Buildup. What happens?
Pyruvate becomes lactic acid. NADH becomes NAD+
Non-cyclic light-dependent photosynthesis
Light absorbed at PSII. 2 electrons in PSII excited and go to ETC. H+ protons go into thylakoid membrane and ATP is produced. Electrons go to PS1 and repeat process. When done, they reduce NADP+ to NADPH.
Cyclic Light dependent photosynthesis
Instead of reducing NADP+ to NADPH, electrons go back to PSII once having gone through the ETC
Where does Calvin Cycle occur?
Stroma (fluid filled space between membranes)
Carboxylation (Calvin)
6 CO2 + 6RuBP = 12 PGA
Reduction (calvin)
12 ATP + 12 NADPH makes 12 PGA into 12 PGAL
Regeneration
Ten of twelve PGAL become 6 RUBP
Carb synth (calivin)
remaining 2 PGAL become glucose
C3 Plants
Photosynthesis efficiency reduced by 25%
Glyoxysomes
Peroxisome equivalent in plants
What structure in plant roots and kidney cells allows for faster osmosis?
Aquaporins
Where is the ETC?
Inner membrane of mitochondria
