Cell Anatomy & Physiology 3 Flashcards
A cell’s characteristic is determined by the type of proteins produced. True or false?
True
The proteins produced are in turn determined by the genetic information in the nucleus. True or false?
True
Information in protein provides the cell with a code for its cellular processes. True or false?
False, it should be DNA not proteins
DNA contains the information that directs protein synthesis; a process called ________
Gene expression
A DNA molecule consists of __________ joined together to form two ___________ strands
nucleotides
Each nucleotide consists of what?
5-carbon sugar, a phosphate group, and a nitrogenous base
a sequence of nucleotides that provides a chemical set of instructions for making a specific protein
Gene
- Found within the cell nucleus
- Stores and transfers genetic information
= Passed from existing cells to new cells during cell division
Deoxyribonucleic acid (DNA)
- Occurs in all parts of the cell
- Vital in the synthesis of proteins
Ribonucleic acid (RNA)
The main structural difference between ribose and 2-deoxyribose is the absence of oxygen on the 1st carbon (counterclockwise from O). True or false?
False, it’s the absence of oxygen on the 2nd carbon
Ribose is present in ____
2-deoxyribose is present in _____
RNA ; DNA
How many nitrogenous heterocyclic bases in nucleic acids?
5 nitrogenous heterocyclic bases
Give the 3 pyrimidine derivatives
- Cytosine (C)
- Thymine (T; found only in DNA),
- Uracil (U; found only in RNA)
Give the 2 purine derivatives
Adenine (A) and Guanine (G)
- Derived from phosphoric acid (H₃PO₄)
- Loses 2 hydrogen atoms, resulting in the formation of a hydrogen phosphate ion (HPO₄2–)
Phosphate
Amounts of A and G were always equal. Amounts of C and U were always equal. True or false?
False, A = T/U ; C = G
Human DNA contains:
30% adenine
30% thymine
20% guanine
20% cytosine
True or false?
True
Guanine always pairs with cytosine, adenine always pairs with thymine in DNA and uracil in RNA aka ___________
complementary pairs
explains the process in which the genetic information flows from DNA to RNA (i.e. gene expression) to make a functional protein product (protein synthesis)
central dogma of molecular biology
creates more copies of DNA using pre-existing DNA as templates
Replication
information from DNA is transferred to a single-stranded RNA
Transcription
RNA enters the ribosome which takes the information and synthesizes long polypeptide chains of amino acids
Translation
DNA replication is catalyzed by __________ which ensures correct base pairing and formation of phosphodiester linkages
DNA polymerase
The other strand grows in segments in the opposite direction
Okazaki fragments
The segments are connected by
DNA ligase
DNA replication usually occurs at multiple sites within the molecule. _____________ occurs at these sites while _____________ enables rapid replication of large molecule
Bidirectional replication ; Multiple-site replication
formed by the interaction of newly-replicated DNA molecules with histones
Chromosomes
A segment of a DNA strand responsible for the production of a specific hnRNA/mRNA molecule
Gene
Most human genes comprise of how many nucleotide units?
1000–3500
All of the genetic material contained in the chromosomes of an organism
Genome
Formed by DNA transcription
Heterogenous nuclear RNA (hnRNA)
Carries instructions for protein synthesis
Messenger RNA (mRNA)
Facilitates the conversion of hnRNA to mRNA
Small nuclear RNA (snRNA)
Combines with specific proteins to form ribosomes
Ribosomal RNA (rRNA)
Delivers amino acids to sites for protein synthesis
Transfer RNA (tRNA)
The information needed to make and order the appropriate sequence of amino acids during translation can be found in the ______
Exons
They are interspersed between exons and undergo splicing to be spliced out.
Introns
A process of producing several different proteins from a single gene. Involves splicing of an nRNA molecule with multiple exons
Alternative splicing
All of the mRNA molecules that can be generated from the genetic material in a genome
Transcriptome
The base sequence of an mRNA molecule involves 4 different bases. These are?
A, C, G & U
A three-nucleotide sequence in an mRNA molecule that codes for a specific amino acid
Codon
The assignment of the 64 mRNA codons to specific amino acids
Genetic code
This is an initiator of protein synthesis
AUG
They are codons that stop protein synthesis
UAA, UAG, and UGA
The process in which mRNA codons are deciphered and a specific protein molecule is synthesized in the ribosome
Translation
The translation process can be divided into three phases. These are?
initiation, elongation, and termination
Act as intermediaries to deliver amino acids to mRNA
Transfer RNA or tRNA
a ribosomal RNA-protein complex that is the site for protein synthesis
Ribosome
the A site binds to the incoming aminocyl tRNA which carries the new amino acid to be added to the polypeptide chain
Aminoacyl Binding Site
the P site holds the tRNA with the growing polypeptide chain
Peptidyl Binding Site
the E site holds the tRNA without its amino acid which is then released by the ribosome
Exit Site
involves the positioning of the translation complex or the elongation-competent 80S ribosome at the initiation codon and requires energy in the form of ATP
initiation
the small subunit reads the mRNA, the larger subunit adds the appropriate amino acid to the polypeptide chain using transfer RNA or tRNA
elongation
occurs when the ribosome reaches a stop codon
Termination
occurs to increase the number of cells or replace damaged or dying ones
cell division
The cell cycle includes two major phases: a nondividing phase, called ______, and a cell dividing phase, termed _______.
Interphase; mitosis
during which the cell carries out normal metabolic activity
G₁ phase
during which the DNA is replicated
S phase
during which the cell prepares to divide
G₂ phase
At the end of interphase, a cell has how many complete sets of genetic material?
Two complete sets
A cell can also enter a ________, sometimes called the alternative phase of the cell cycle. Some cells enter this phase temporarily until an outside signal triggers the onset of G₁
G₀ phase
involves the formation of 2 daughter cells from a single parent cell.
Mitosis
The chromatin condenses to form visible chromosomes. Microtubules, termed spindle fibers, form to assist in breaking the centromere between the chromatids and move the chromosomes to opposite sides of the cell. The nuclear membrane dissolves.
Prophase
The chromosomes align near the center of the cell. The movement of the chromosomes is regulated by the attached spindle fibers.
Metaphase
the chromatids separate and each chromatid is called a chromosome. Each of the two sets of chromosomes is moved by the spindle fibers toward the centriole at one of the poles of the cell. At the end of this phase, each set of chromosomes has reached an opposite pole of the cell, and the cytoplasm begins to divide.
Anaphase
The chromosomes in each daughter cells become organized to form two separate nucleim one in each newly formed daughter cell. The chromosomes begin to unravel and resemble the genetic material during interphase.
Telophase
The process by which cells develop with specialized structures and functions is called __________
differentiation
labile commitment or able to be altered, depending of different factors
Specification
stable commitment or irreversible specification, regardless of other factors in its environment
Determination
overt change of the initial cell into a specific cell type
Differentiation
termed programmed cell death, is a normal process by which cell numbers within various tissues are adjusted and controlled.
Apoptosis
