Exam 1 Flashcards
gene
- unit of heredity
- coded/ conceded information in DNA
genetics
- scientific study of heredity
- broad field bc its the key to all of biology
- controls cellular function and links living organisms
modern genetics
- confluence of advances made while studying many organisms
- ex. bacteria, yeast, insects, plants, etc.
4 classes of modern genetics
- transmission genetics
- cytogenetics
- molecular egentics
- population genetics
transmission genetics
- studies mechanisms by which traits are passed from parents to offspring
- ex. fruit flies
cytogenetics
- used to map genes, study chromosome structure, identify abnormalities
- ex. comparing normal cells w cancer cells
molecular genetics
- chemical nature of genes (how genetic info is encoded, replicated, + expressed)
- utilizes recumbent DNA, technology to identify, isolate, clone and analyze genes (genetic engineering)
- greatest impact on genetics since 1980s
population genetics
- distribution + variation of genes in populations
- explains migration, pop size, natural selection
- “stats”
pedigree analysis
- used instead of mating experiments (animals)
- goal: assess risk to future generations
karyotyping
-method used to visually analyze chromosomes in cytogenetics
what makes model genetic organisms useful for genetic analysis?
- short generation time
- manageable # progeny
- adaptability to lab environment
- ex. zebrafish
is genetics new?
- NO
- ancient hunter-gatherers domesticated plants and animals (agrarian society)
artificial selection (way back when)
- collected seeds from plants w/most desirable traits
- bred only prized animals
germplasm
- haploid (n) sex cell
- ancient farmers preserved seeds, cuttings, etc.
- preserved and traded genetic stocks
pangenesis
- concept beloved first by ancient greeks
- inheritance of acquired characteristics (your offspring carry your knowledge as well as all the generations before you)
preformationism
-inside egg or sperm exists tiny mini adult/ homunculus
cells
- basic unit of life
- either eukaryotic or prokaryotic (single celled, no nucleus)
cells
- basic unit of life
- either eukaryotic or prokaryotic (single celled, no nucleus)
genetic info is ________ from DNA to RNA and then _______ from RNA to protein
- transcribed form DNA to RNA
- translated from RNA into protein
mutations
- permanent heritable changes in genetic info
- gene mutations: affect single gene
- chromosomal mutations: affect many genes
evolution
-genetic change
allele
- variation of a gene/ certain trait
- ex. green eyes
allele
- variation of a gene/ certain trait
- ex. green eyes
chromosome
- two sister chromatin held together by the centromere
- encodes for DNA
- chromosome can consist of single chromatid, or 2/ sister chromatids
chromatin
- packaged DNA using histone proteins in the nucleus
- condensed/ wound into chromosomes
telomere
- natural ends/ tips of a linear chromosome
- stabilize and protect ends from degrading (for aging and cancer)
telomere
-natural ends/ tips of a linear chromosome
centromeres
- attachment points for spindle fibers to pull apart chromatids
- metacentric: middle
- submetacentric: off-center
- acrocentric: far to one side
- telocentric: v shape
3 essential elements functional chromosomes have
- a centromere
- pair of telomeres
- origin of replication (make 2 sister chromatids from 1)
the cell cycle
- sequence of events between divisions
- interphase
- mitosis/ “M-phase”
- cytokinesis
interphase
- occurs after cells have divided
- where cells grow and mature in 3 stages:
- Gap 1 (G1): RNA, proteins made
- S (synthesis): DNA replicated
- Gap 2 (G2): preparing for cell division
- chromosomes replicated in interphase
mitosis/ M phase
- chromosomes are replicated into 2 daughter cells 46X2
- prophase
- pro-metaphase
- metaphase
- anaphase
- telophase
- cytokinesis
prophase + pro metaphase
(-chromosomes already replicated in interphase)
- chromosome condense into longitudinal strands (chromatin)
- chromatids join at centromere to form sister chromatids
- nuclear envelope breaks down
- spindle fibers/ microtubules attach
cytokinesis
-division of cytoplasm
anaphase
-centromeres divide to convert each sister chromatid into a chromosome
telophase
- chromosomes reach opposite ends of the cell and decondense
- nuclear envelopes reform
- belt forms/ 2 cells start to take shape
telophase
- chromosomes reach opposite ends of the cell and decondense
- nuclear envelopes reform
- 2 cells start to take shape
cytokinesis
-cleavage furrow forms, deepens, and cytoplasm divides to yield two daughter cells (diploid/ 2n)
diploid / 2n
- daughter cells after cytokinesis
- have 2 copies of each chromosome (genetically identical)
- 23 pairs, 46 total
somatic cells
- in mitosis
- most cells in the body (non reproductive)
gametes / germline cells
- sex cells (egg + sperm)
- cells divided in meiosis
- haploid (n)
- one copy of each chromosome
- 0 pairs, 23 total (not genetically identical!)
fertilization
- fusion of gametes
- restores number of chromosomes back to 23 PAIRS, 46 total (2n)
- fert egg= diploid/ 2n and can develop properly
meiosis
- diploid (2n) cells undergo replication and then 2 rounds of division
- end up with haploid (n) gametes
random assortment
- how meiosis produces new combinations of genes (way 2)
- maternal ans paternel chromosomes are lined up indiscriminately alone metaphase 1 plate
- 70 billion possibilities
sex chromosomes
- determines if human is male or female
- XY or XX
sex chromosomes
- determines if human is male or female
- XY or XX
pieces of what are being exchanged in homologous recombination?
-pieces of chromatids of homologous chromosome pair
in which phases are sister chromatids separated from each other?
- anaphase of meiosis +
- anaphase 2 of mitosis?
monohybrid crosses
- one differ in one gene
- Mendel’s first cross: P1
- Mendel did seed shape (smooth vs. wrinkled)
a gene is a segment of DNA that has the information to produce a functional product. The functional end product of most genes is _______.
-a polypeptide
variation in the traits of an organism may be attributed to which of the following?
- levels of gene expression
- gene mutations
- alterations in chromosome structure
- variation in chromosome number
image of cell splitting with no nucleus (just chromosome dividing)
- shows binary fission
- no nucleus so not mitosis or meiosis
how many chromatids would be present in a single cell at metaphase II for an organism that has a euploid state in which its somatic cells are diploid and contain 8 chromosomes?
8
a human retinal cell has 46 chromosomes, how many chromosomes are found within a human egg cell?
23
a diploid organism has 6 chromosomes total at G1, how many chromatids would be present in a cell from the same organism at anaphase 1?
12
order of 4 major branches of modern genetics from macroscopic to microscopic
- population
- transmission
- cytogenetics
- molecular
a person studying the rate of transcription of a particular gene is working in which of the fields of genetics?
-molecular genetics
