Biology Flashcards
Do prokaryotic cells contain a nucleus?
NO!!!
Membrane-bound Organelles found in eukaryotic, prokaryotic, or both?
ONLY EUKARYOTES
The nucleolus is…
A subsection of the nucleus where ribosomal RNA (rRNA) is synthesized!!
rRNA – RNA component of ribosomes
Cytoplasmic/Extranuclear Inheritance
the transmission of genetic material independent of the nucleus
MITOCHONDRION – contain own genes and replicate independently of the nucleus through binary fission
Apoptosis
MITOCHONDRION
release enzymes from the ETC kickstarts apoptosis
Difference between rough ER and smooth ER?
Rough ER studded with ribosomes and translated proteins.
Smooth ER used for lipid synthesis and detoxification. Also transports proteins from RER to Golgi.
Primary function of a peroxisome?
breakdown of very long chain fatty acids via beta oxidation
Microfilaments
Component of the cytoskeleton. Solid polymerized rods of actin. RESISTANT TO COMPRESSION OR FRACTURE. Interact with myosin to generate movement.
Role in CYTOKINESIS (division of material between daughter cells). Creates cleavage furrow between two daughter cells (ring of actin filaments).
Microtubules
Component of cytoskeleton. Hollow polymers of tubulin. Pathway for KINESIN and DYNEIN.
What is the 9+2 structure?
Pertaining to the structure of cilia and flagella. Composed of nine pairs of microtubules forming an outer ring with two microtubules in the middle.
ONLY IN EUKARYOTES
Centrioles
Found in the CENTRISOME. Organize the mitotic spindle on opposite ends of cell. Microtubules emanate from centriole and attach to chromosome via the KINETOCHORE.
Parenchyma
The functional parts of an organ. Comprised of EPITHELIAL cells in many organs. Attached via basement membrane.
Stroma
The support structure of an organ for the endothelial cells. Comprised primarily of CONNECTIVE TISSUE.
Nucleoid Region
Found in PROKARYOTES.
Region where the single circular molecule of DNA is found.
Obligate Aerobe
bacteria that require oxygen for metabolism
Obligate Anaerobes
bacteria that cannot survive in an oxygen-containing environment
Facultative Anaerobe
bacteria that can toggle between aerobic and anaerobic respiration depending on what’s available
Describe the membrane/outside of a prokaryote.
CELL WALL outer barrier of the cell
CELL/PLASMA MEMBRANE
these together are known as the ENVELOPE of the prokaryote
Gram-positive vs gram-negative prokaryotic cell walls.
Gram-Positive: thick layer of peptidoglycan (PURPLE) and lipoteichoic acid
Gram-Negative: very thin layer of peptidoglycan separated by periplasmic space (PINK) and lipopolysaccharides
Plasmids
carry DNA in prokaryotes NOT NECESSARY for survival
NOT part of the genome
ETC in prokaryotes.
They lack mitochondrion
Instead, use the cell membrane for the ETC.
Ribosomal difference between eukaryotes and prokaryotes.
Prokaryote: 30S and 50S (SMALLER)
Eukaryotes: 40S and 60S (LARGER)
A subset of plasmids capable of integrating into the genome of a bacteria cell?
Episome
Transformation
integration of foreign genetic material into the host genome
Conjugation
Sexual reproduction in bacteria. Unidirectional via a conjugation bridge.
How is a Hfr (high frequency of recombination) bacterium formed?
The sex factor is integrated into a bacterium genome. The conjugation bridge breaks before the entire copy of the genome is transferred to the recipient. This bacterium is now Hfr.
Transduction
only genetic recombination process that requires a vector – virus carries material from one to another.
BACTERIOPHAGE
Transposon
genetic elements capable of inserting and removing themselves from the genome
Growth Phases of a Bacterial Colony
- Lag Phase
- Exponential (Log) Phase
- Stationary Phase
- Death Phase
via binary fission
Capsid
Protein coat of a virus which may be surrounded by an envelope composed of phospholipids
Enveloped Virus
EASIER TO KILL (prone to heat, detergents, and desiccation)
Virion
the viral progeny produced in an infected host cell
Negative-sense RNA viruses
MUST carry with them an RNA replicase in the virion to ensure complementary RNA strand is synthesized
Retrovirus
ENVELOPED
SINGLE-STRANDED RNA
carry the enzyme reverse transcriptase (synthesizes DNA from the RNA) – this then integrates into the host genome
Enzyme responsible for creating complementary RNA (+) from a negative sense RNA virus.
RNA replicase
Lytic Cycle
bacteriophage maximizes the use of the cell’s machinery without regard for life
busts out the hoe like a bomb
very virulent
Lysogenic Cycle
integration into the host genome or acts as a prophage (exits the cell but keeps it intact)
acts as a sneaky bastard and gets replicated
superinfection
Prions
infectius proteins due to triggering the misfolding of other proteins
usually through conversion of alpha helix to a beta-pleated sheet
Cytokinesis
the cytoplasmic division in eukaryotes at the end of mitosis (cell separation)
invagination of the cell membrane
How many chromosomes do humans have?
46 total (autosomal cells // two copies of each chromosome) [diploid]
23 from each parent (germline cells // haploid)
Which stages of the cell cycle make up interphase? What is interphase?
G1, S, and G2
longest part of the cell cycle
What stage of the cell cycle are cells that don’t divide in?
An off shoot of G1 called the G0 stage.
What form are chromosomes in during interphase?
less condensed version called CHROMATIN
must be available to RNA polymerase
G1 Stage of the Cell Cycle
Presynthetic Gap
cells create organelles
passage to the S stage is governed by a restriction point
S Phase of the Cell Cycle
Synthesis of DNA
cell replicates its genetic material
chromatids bound together at the centromere
46 chromosomes with 92 chromatids (2x DNA than G1 cells) organized into 23 homologous pairs
G2 Stage of Cell Cycle
Postsynthetic Gap
quality control checkpoint for DNA replication before cell divides
M Stage of the Cell Cycle
NOT Interphase
Mitosis
mitosis and cytokinesis
G1/S and G2/M checkpoints in the cell cycle regulated by what?
p53 main protein responsible to check if the condition of the DNA is good enough for synthesis
What is one of the most common mutations found in cancer?
mutation of the gene TP53
the gene that produces the p53 protein
Prophase (Mitosis)
chromosomes condense and spindle forms
centrosomes – microtubule organizing center – migrate to ends of cell
kinetochores
Metaphase (Mitosis)
chromosomes align at the metaphase plate (equatorial plate)
Anaphase (Mitosis)
sister chromatids separate
kinetochore fibers shorten
Telophase (Mitosis)
new nuclear membranes form
cytokinesis
Telophase (Mitosis)
new nuclear membranes form
cytokinesis
Meiosis I vs Meiosis II
Meiosis I results in homologous chromosomes separating (haploid daughter cells) (reductional division)
Meiosis II results in the separation of sister chromatids without a change in ploidy (equatorial division // more similar to mitosis)
Mitochondrial DNA
CIRCULAR and SELF-REPLICATING
Which organelles are surrounded by a single membrane and which are surrounded by a double membrane?
SINGLE: lysosome
DOUBLE: mitochondrion and nuclei
A virus needs to be transported into the nucleus in order to synthesis viral proteins. What is the genomic content of the virus?
DNA virus!!!
only DNA virus need host nuclear RNA polymerase
Crossing Over
during Prophase I of meiosis, homologous chromosomes come together in a process called synapsis
each synaptic pair contains four chromatids called a tetrad; these break at the chiasma
DNA is exchanged via crossing over
NOTE: this happens between HOMOLOGOUS CHROMOSOMES and not between sister chromatids
Linked Genes and recombination via crossing over
Linkage refers to the tendency of genes to be inherited together
genes that are farther away are less likely to be linked and more likely to undergo crossing over relative to each other
Ploidy through Mitosis vs Meiosis
note: n = 23
Mitosis: 2n –> 2x 2n
Meiosis: 2n –> 2x n (Meiosis I; split homologous pairs) –> 4x n (Meiosis II)
What is the SRY gene?
The SRY (sex-determining region Y) is a gene on the Y chromosome which encodes for transcription factors that initiates testis differentiation
Sertoli cells
essential for spermatogenesis
nourish the formed sperm cells in the seminiferous tubules
Leydig cells
secrete testosterone and other androgens
Acrosome
cap on the head of a sperm
derived from the golgi apparatus and is necessary to penetrate the ovum
Primary Oocytes
the oogonia that have already undergone DNA replication at birth
2n cells arrested in Prophase I
after menarche, one will complete meiosis I each month and produce a secondary oocyte (n) and polar body
Secondary Oocyte
arrested in Metaphase II (n)
will only complete the remainder of meiosis II if fertilized by a sperm cell
Describe hormonal control prior to and during puberty in a female/
Before puberty: the hypothalamus restricts the production of GnRH (gonadotrophin-releasing hormone)
Puberty: hypothalamus produces GnRH, which triggers the anterior pituitary gland to release FSH (follicle-stimulating hormone) and LH (luteinizing hormone)
Hormonal control of male sexual development
FSH stimulates Sertoli cells and triggers sperm maturation and LH causes the interstitial cells to produce testosterone
testosterone results in the development of secondary sex characteristics
Hormones and the menstrual cycle
Estrogen is secreted in response to FSH and results in the development and maintenance of the female reproductive system; leads to thickening of the endometrium
Progesterone is secreted by the corpus luteum (remains of ovarian follicle after ovulation) in response to LH; development and maintenance of the endometrium
Follicular Phase of Menstrual Cycle
begins with the menstrual flow
GnRH increases due to estrogen and progesterone drop off; this leads to increased FSH and LH
these develop ovarian follicles which begin to produce estrogen and negative feedback inhibit GnRH, FSH, and LH
Ovulatory Phase of the Menstrual Cycle
Estrogen reaches a point where it positive feedback on GnRH, FSH, and LH
the spike in LH induces ovulation
Luteal Phase of Menstrual Cycle
LH causes follicle to form corpus luteum which secretes progesterone
progesterone and estrogen both high and inhibit GnRH, LH, and FSH
Blastulation
First phase of development
solid mass of cells called a morula and then the blastula which implants in the endometrium
Gastrulation
occurs after blastulation
generation of three distinct cell layers
archenteron (membrane invagination) and blastopore (opening of archenteron…turns into anus)
Primary Germ Layers
Ectoderm
- outermost; integument and nervous system
Mesoderm
- middle layer; muscular and connective tissue, circulatory
Endoderm
- epithelial lining of digestive and respiratory
Neurulation
development of the nervous system
notochord (mesoderm) induces neural folds (ectoderm) and neural crest cells
Neurulation
development of the nervous system
notochord (mesoderm) induces neural folds (ectoderm) and neural crest cells
Kinesin vs Dynein direction
Kinesin = ANTEROGRADE movement on microtubule
Dynein = RETROGRADE movement on microtubule
What is the role of fallopian cilia?
they PROPEL the fertilized oocyte forward into the uterus for proper implantation
