staff im struggling with Flashcards
- Enzymes
class of protein with a specific shape, and unique function. All enzymes have an active site, which is a specialized structure which binds to a ligand.
ligand
is the molecule the enzyme binds to either perform a catabolic, anabolic, or other function.
- Gibbs free energy
– Measures the amount of energy through a reaction. The energy at the start must be higher than the energy at the end.
how can delta g be favorable
If you have a positive delta G that is unfavorable as it requires energy, be put into the reaction. Negative delta G are favorable and exergonic.
- Anabolic reactions
Build up larger macromolecules from smaller building blocks.
examples of anabolic reaction :
- Glucose being polymerized into glycogen and DNA synthesis transcripts and translation are all anabolic reactions.
- Catabolic reactions
: break down larger macromolecules into smaller building blocks.
example of catabolic reactions
Digestion is a good example of a catabolic reaction.
- Protein Structure
sequence yields structure which yields function. The sequence of amino acids in protein is dictated by specific sequence of DNA, which yields a specific sequence of nucleotides in RNA, Which during translation is translated to amino acids sequence. The sequence of amino acids is the primary structure of protein.
The quaternary level consists of :
2 or more tertiary structures interacting for the same reasons tertiary structures form.
secondary structures can interact with one another via :
covalent, ionic, and hydrophobic interactions.
- Lipids
Are a class of macromolecules which have a hydrophilic portion and a hydrophobic protein with long hydrocarbon tails.
Saturated lipids
have only single covalent bonds between carbon
unsaturated
tails have double bonds that allow for flexibility.
cell membrane is composed of a :
phospholipid bilayer
lipid bilayer
due to the hydrophilic heads being able to make associations with water molecules with charged oxygen resides on the phosphate.
- Cell membranes are a mix of
saturated and unsaturated phospholipids
Concentration gradients
consist of a barrier of some kind, usually a cell membrane, and particles. Particles will always travel down a concentration gradient towards the side where there are less.
Channels
: channel proteins work with concentration gradients, and do not require energy (ATP) allowing the imbalance to be corrected.
Pumps:
Use chemical energy (ATP), and work against concentration gradients.
Adhesion proteins:
Cells are often linked to other cells or to basement membranes.
Receptor proteins:
Cells communicate with one another and interact with their outside environment.
DNA
Deoxyribonucleic acid
Transcription
: the process of copying a sequence of DNA (a gene) into messenger RNA (mRNS) form.
genome:
is composed of 23 pairs of (but is 46 without the pairs) chromosomes in the nucleus
3 billion base pairs 98% of the genome is regulatory, ancestral viral in origin, and some of it are nonsense sequences. The other 2% of the genome constitutes genes.
Gene:
a sequence of DNA which codes for a protein.
Transcription:
the process of creating an MRNA molecule from a DNA templet, using the enzyme RNA – Polymerase.
Transcription: consists of 3 steps
- Initiation: the RNA polymerase lands on the promoter region and begins traveling towards the gene.
- Elongation: As soon as the start codon is reached, elongation begins. Elongation continues until a stop (one of the 3) codon is reached.
- Termination: once the stop codon has reached the completed MRNA module and the enzyme floats away.
Ribosomes:
are where translation takes place. Ribosomes are made of ribosomal RNA (rRNA) There are two types, 80s which are found in Eukaryotes, and 70s which are found in bacteria, chloroplasts, aid the mitochondria
tRNA (transfer RNA)
Carry anti- codons and one of the 20 amino acids.
A “charged “tRNA
carries an amino acid
uncharged tRNA
one has given its amino acid to the growing protein chain and is “empty “or uncharged.
The ribosome translocate, which shifts tRNA from A to P to E What is A
the A site (except for the first one) accepts incoming holding amino acid binds with the previous amino acid
what is p TRNA
at the p- site always holds the growing chain of amino acids
what is E for trna
E site always holds empty tRNA’s and the next the ribosome translocate the tRNA is ejected out.
Translation steps 3
Initiation 1: the ribosome assembles around the MRNA, and the start codon is positioned at the p – site.
Elongation 2. As soon as the first tRNA lands elongation begins. What is elongation is the chain of amino acids at the p-site. The ribosome continues to translocate and accept amino acids until a stop codon is reached.
Termination 3: Once the stop codon is reached the ribosome disassembles and the completed protein is let go, and it folds into its tertiary structure.
Chromosomes
are large sequences of DNA wrapped around histone proteins.
Mitochondria
Supplies the majority of ATP for the cell. The mitochondria have 70s ribosomes because in the distant past it was a free – living bacteria, which has taken in by the first eukaryotic cell.
Rough endoplasmic reticulum
Is covered in 80s ribosomes. Proteins which are sent to the cell membrane or out of the cell.
* Free floating 80s ribosomes translate proteins which stay within the cell.
Smooth Endoplasmic reticulum:
Produces phospholipids, stores intracellular calcium, and acts as a detoxification center.
Golgi body
a cellular sorting station which accepts vesicles carried by kinesin and then floats vesicles to the membrane.
Lysosomes:
contain digestive enzymes and low ph.
Digestive enzymes:
Involved in apoptosis which is programmed cell death and the lysosomes pop and poison the cell form within.
Mitosis:
is for growth and repair: Not all cell types divide, such as neurons, or muscle cells (Smooth, cardiac, and skeletal) The cell spends most of its time in a process called Interphase which takes place before mitosis.
- Interphase:
the stage before mitosis): consist of three phases, G, S, and G2,
G, and G2 are both phases and S stands for synthesis
G
The cell grows and translates necessary enzymes and other proteins for cell direction. Nervous and muscle cells are arrested at this step and do not enter s phase.
S :
s stands for synthesis. During this stage chromosomes are replicated via DNA – Polymerase. Before S-phase, in humans there are 23 pairs (46 chromosomes). Since the genome is replicated in s-phase, after it the cell has 92 chromosomes or 4 copies of each chromosome. At this point, the cell must divide.
G2:
An additional growth phase following s-phase, where final check points are made before mitosis begins.
Mitosis (PMAT)
Prophase , Metaphase , anaphase , telophase
Prophase:
the nucleus begins to fade away and eventually is dissolved. Chromosomes condense, and spindle fibers from centrioles connect to chromosomes (the button looking portion of the chromosome.) Chromosomes begin to migrate (pulled by spindle fibers) towards the center of the cell.
Metaphase
Chromosomes line up at the metaphase plate along the equator of the cell.
Anaphase:
Chromosomes begin to migrate to opposite ends of the cell, along with their homologous chromosomes. Humongous means like, so chromosome 1 having 2 copies are homologous.
Telophase:
the cleavage furrow forms due to a microtubule wrapped around the cell. The nucleus begins to reform around each copy of the genome (23 pairs of chromosomes)
- Cytokinesis
The cell evenly divides the cytoplasm (the cytoplasm plus all organelles except the nucleus) At this point, each new cell has 23 pairs of chromosomes and is now in G, of interphase
Meiosis:
Is not the same as mitosis, and one does not lead into the other. Meiosis produces gametes which are eggs or sperm. The mechanism of meiosis is similar to mitosis but doesn’t combine the processes.
Homologous chromosomes
exchange sequences of DNA
holiday junctions
which are resolved via proteins which cut strands
Stem Cells
totipotent stem cells can become any cell type including extraembryonic tissue. (like the placenta) In the embryo, totipotent stem cells have fates to become certain cell types depending `1g on their spatial position
Pluripotent stem cells
can become any cell type, but not extra embryonic tissue.
Multipotent stem
Can become red blood cells, white blood cells, and megakaryocytes cells produce platelets.
Embryogenesis:
After the formation of the zygote the cell rapidly divides and becomes various cell types in the embryo.
There are 3 germline stem cell types which form all tissues of the body.
ectoderm, endoderm, mesoderm
- Ectoderm
forms nervous and epithelial tissue
- Endoderm:
forms all glands and organs such as the lungs, kidneys, liver and pancreas…
- Mesoderm:
forms all 3 muscle types (skeletal, cardiac, and smooth.)
QTL : Quantitative trait loci
These traits are formed due to multiple regions of the genome all contributing to the same trait.
What are the layers of bone that Develop bone length :
1st layer – resting cartilage (contains stem cells)
2nd layer – proliferating cartilage (where cells are rapidly going through mitosis)
3rd layer – hypertrophic (cartilage cells begin to transition into new bone layer)
How does a bone gain gurth:
grow in girth by the endosteum layer being broken down by osteoclasts, and the periosteum layer being built up by osteoblasts. This continues until adulthood when the bones stop growing.
How does a bone gain gurth:
grow in girth by the endosteum layer being broken down by osteoclasts, and the periosteum layer being built up by osteoblasts. This continues until adulthood when the bones stop growing.
