ksafa Flashcards
Characteristics of life
- Growth and Development
2.Maintain Homeostasis
- Reproduction
- Response to Environment or Stimuli
- Energy Processing
- Organized
It is any part of an organism’s environment that causes reaction
Stimulus
It is a common method of modification of the heat exchange for most mammals.
Piloerction
is the most common photosynthetic process and is seen in algae, cynobacteria and plants
Oxygenic photosynthesis
photosynthetic process that makes use of electron donors other than water
Anoxygenic Photosynthesis
enzymes that are retained intracellularly & function within the cell
Endoenzymes
enzymes transported extracellularly, where they break down large food molecules or harmful chemicals; cellulase, amylase, penicillinase
Exoenzymes
Control of enzyme synthesis
enzymes that are always present, always produced in equal amounts or at equal rates, regardless of amount of substrate; enzymes involved in glucose metabolism
Constitutive Enzymes
Control of enzyme synthesis
enzymes not constantly present, produced only when substrate is present, prevents cell from wasting resources
synthesis of these enzymes is induced by a metabolite
Induced Enzymes
Control of enzyme synthesis
Enzymes not produced when the end product of the pathway is present
synthesis of these enzymes is suppressed by a metabolite
Repressible Enzymes
Control of enzyme activity directly
Occurs when a substance that resembles normal substrate competes with substrate for active site
Competitive Inhibition
Control of enzyme activity directly
Characterized by a substance binding to the cofactor and distorts the shape of the active site
Noncompetitive Inhibition
Control of enzyme activity directly
Control mechanism wherein the concentration of product at the end of a pathway blocks the action of a key enzyme
Feedback Inhibition
Control of Enzyme Activity Categories
- Control of enzyme activity directly
- Control of enzyme activity by regulating enzyme synthesis
These are anabolic reactions to form covalent bonds between smaller substrate molecules, require ATP, release one molecule of water for each bond
Synthesis/condensation reactions
These are catabolic reactions that break down substrates into small molecules, requires the input of water
Hydrolysis Reactions
a type of chemical reaction that involves a transfer of electrons between two species.
Oxidation-Reduction Reaction
They convert one type of amino acid to another by transferring an amino group
Aminotransferases (or transaminases)
The transfer of phosphate groups, involved in energy transfer
Phosphorylation
Three types: Photophosphorylation, Substrate level phosphorylation, Oxidative phosphorylation
a model for enzyme-substrate interaction suggesting that the enzyme and the substrate possess specific complementary geometric shapes that fit exactly into one another.
Lock and Key Model
a model for enzyme–substrate interaction to describe that the substrate is capable of inducing the proper alignment of the active site of the enzyme, causing the latter to subsequently perform its catalytic function.
Induced Fit Model
Enzymes that contain protein (apoenzyme) and nonprotein (cofactors) molecules
Conjugated Enzymes or holoenzymes
Enzymes consisting of proteins alone
Simple enzymes
- biosynthesis
- building complex molecules from simple ones
- requires energy (ATP)
Anabolism
- degradation
- breaking down complex to simple molecules
- generates energy (ATP)
Catabolism
The sum total of all chemical reactions and physical workings occurring in a cell
Metabolism
- For a reaction to occur, an energy barrier must be surmounted
- the minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction
Activation Energy
- Point when a reaction can easily run in either direction, to product or back to reactant
- Unstable at the highest energy level
- Substrate is bound most tightly to an enzyme in this state
Transition State
is where a small part of the chromosome is moved to another chromosome.
Translocation
is where a portion or part of the chromosome is lost during the cell division and the result is mostly lethal
Deletion
happens if the fragment joins the homologous chromosome, then that region is repeated
Duplication
- some call this as chromosomal rearrangements.
- In this disorder, there is a part of chromosome that is affected
Chromosomal Alterations
- has 45 chromosomes because there is no Y chromosome
- They are genetically female, but they do not mature sexually during puberty
Monosomy X (Turner’s Syndrome)
- has 47 chromosomes and this time there are three X chromosome and no Y chromosome
- female
- Their distinct features include widely spaced eyes, abnormally curved pinky fingers, flat feet and abnormally shaped breastbone
Trisomy X (Triple X Syndrome)
- has 47 chromosomes, just like Klinefelter, but this is because there is a pair of Y chromosome instead of just 1
- Person with this abnormality has no distinct physical features and mostly show behavioral difference
XYY Syndrome
- has 47 chromosomes because there is a pair of X chromosome instead of just 1
Klinefelter’s Syndrome
- occurs when pairs of homologous chromosomes or the sister chromatids fail to separate during anaphase I or anaphase II (rare in mitosis)
Nondisjunction
- From the name itself, it implies that there is an excess chromosome in chromosome 21.
- down syndrome
Trisomy 21
- this means that there is an excessive copy of chromosome (normally it is a pair (2) but in these cases, there are 3 chromosomes)
Excessive Chromosomes (Autosomes)
it is the abnormality in the number of chromosomes; either there is too much or too few
Aneuploidy
- it is the production of female gametes (ova) within ovaries (sometimes it happens in the oviduct)
- starts during fetal development
Oogenesis
is the haplid cell which is formed by meiosis in spermatocytes
Spermatid
Differentiation of spermatids to spermatozoa
Spermiogenesis
- complete process of meiosis I and meiosis II to produce 4 spermatids
Spermatocytogenesis
CAUSES OF VARIATIONS
- Crossing Over in Prophase I
- Independent Assortment in Metaphase I & II
- Random Fertilization
differences between members of population
Variation
- produces body/somatic cells
- produces diploid cells
- daughter cells are genetically identical
- cell division and replication occurs ONCE
Mitosis
Mitosis
- chromosomes condense
- microtubules form
- nuclear envelope breaks down
Prophase
Mitosis
- chromosomes are pulled to the center of the cell
- Line up along “metaphase plate”
Metaphase
Mitosis
- centromeres divide
- spindle fibers pull one set of chromosomes to each pole
- Precise alignment is critical to division
Anaphase
- Nuclear enveope form around the chromosomes
- chromosomes uncoil
Telophase
- Found majority on eukaryotic cells and considered as the largest organelle, accounting for around 10% of the cell’s volume
Nucleus
- is the process of selectively permeable nuclear envelope separates the contents of the nucleus from that of the cytoplasm
Cell Compartmentalization
- Major site of synthesis in the cell
- This is a flattened sac network (cisternae) that is continuous with the outer nuclear membrane
Endoplasmic Reticulum
- takes proteins from the cytosol and continues its production in the golgi apparatus until completion
Rough Endoplasmic Reticulum
is important in lipid, phospholipid and steroid synthesis
Smooth Endoplasmic Reticulum
- Mostly present in eukaryotic cells which is responsible for packaging of macromolecules into vesicles so that is can be sent out to their site of action
Golgi Apparatus
- It has inner and outer membrane with an intermembrane space in between
- The outer membrane contains proteins known as porins that enable ion movement to and from mitochondrion
- The inner membrane includes a number of enzymes such as ATP synthase that produces ATP in the matrix and carries proteins that control metabolite movement into and out of the matrix
Mitochondria
- An acidic membrane-bound organelle that contain numerous hydrolytic enzymes which catalyze hydrolysis reactions
Lysosomes
- Consists of single membrane and granular matrix scattered in the cytoplasm
- Contain enzymes involved in a variety of metabolic reactions including several aspects of energy metabolism.
Peroxisomes
- Surrounded by a membrane called tonoplast which encloses fluid containing inorganic materials like water and organic materials like nutrients and enzymes
Vacuoles
A membrane-bound organelle containing liquid or cytosol which is enclosed by a lipid bilayer.
Vesicles
It is a type of plastid that involved in photosynthesis in plants and algae.
Chloroplast
Non-membrane
- It is a structure of cells which produces protein
- Many cellular functions such as repairing damage or directing chemical processes require protein
Ribosomes
Non-membrane
- It is an organelle that helps cell divide or make copies of themselves
- Each cell has a pair of these in the centrosome, a region near the nucleus
Centrioles
Non-membrane
- It is a network of microscopic molecular filaments found in the cytoplasm of all nucleated eukaryotic cells
Cytoskeleton
Cell Modifications
- Also called brush/striated border
- They are finger-like cytoplasmic extensions of the apical surface which increase surface area for absorption
Microvilli
Cell Modifications
Appears as short hair-like structures or projections
Cilia
Cell Modifications
- They have the same axial structure with cilia but much longer that also functions with movement
Flagella
Cell Modifications
- They support the epithelium and also functions as a passive molecular sieve or ultrafilter
Basal Infoldings
Cell Modifications
- They are intercellular adhesion complexes in epithelia and endothelia that control paracellular permeability
Tight Junctions
Cell Modifications
- This is an element of the cell-cell junction in which cadherin receptors bridge the neighboring plasma membranes via their hemophilic reactions
Adherens Junction
- is one of the essential structures common to all cell types
- It acts as a barrier that separates the cytoplasm from the cell’s outer surroundings
Cell or Plasma Membrane
- a two-layer of phospholipid oriented in opposite direction
- A phospholipid molecule consists of a glycerol molecule bonded to a phosphate “head” group and two fatty-acid “tails”.
Phospholipid Bilayer
Phosphate head:
- means attracted to water molecules
Hydrophilic
Phosphate tail:
- means water-dreading or it repels water
Hydrophobic