Chapter 3 Flashcards
These are structures within living cells that contain genes
Chromosomes
Chromosomes are biochemically composed of these two materials
DNA and proteins
In eukaryotes, this is the DNA-protein complex
Chromatin
Eukaryotic chromatin may also contain these
Non-coding RNAs
These two groups of organisms are prokaryotic
Bacteria and archaea
These four groups of organisms are eukaryotic
Protists, fungi, plants, animals
Do prokaryotic cells contain a nucleus?
No
What shape of chromosome do prokaryotes have?
Circular
Prokaryotic chromosomes are found in this region of the cytoplasm
Nucleoid
This encloses the cytoplasm and regulates nutrient uptake and waste excretion
Plasma membrane
What are two examples of additional cell structures that prokaryotes may have?
Outer membrane and flagellum
Eukaryotic cells have these, the major difference between them and prokaryotes
Membrane-bound organelles
This organelle contains most of the genetic material of a eukaryotic cell
Nucleus
What is the shape of eukaryotic chromosomes?
Linear
What are three other examples of membrane-bound organelles found in eukaryotic cells (other than the nucleus)?
Mitochondria, lysosomes, Golgi apparatus
These organelles are responsible for ATP synthesis
Mitochondria
Do mitochondria contain their own DNA?
Yes
These organelles play a role in the degradation of macromolecules
Lysosomes
This organelle plays a role in protein modification and trafficking
Golgi apparatus
What are the two types of animal cells?
Somatic and germ cells
This type of animal cell includes body cells other than gametes (blood cells, for example)
Somatic cells
This type of animal cell includes gametes (sperm and egg cells)
Germ cells
What field of genetics involves the microscopic examination of chromosomes?
Cytogenetics
This is an organized representation of the chromosomes within a cell
Karyotype
Most eukaryotic species are this, meaning they have two sets of chromosomes
Diploid
How many total chromosomes do humans have?
46 (23 sets)
How many total chromosomes do dogs have?
78 (39 sets)
How many total chromosomes do fruit flies have?
8 (4 sets)
Members of a pair of chromosomes are called these
Homologs
What are three characteristics of a homologous pair of chromosomes?
- Nearly identical in size; 2. Have same banding/centromere location; 3. Have same genes
Do homologous chromosomes have to have the same alleles?
No
How much difference in DNA sequence is there in homologous chromosomes?
< 1%
This pair of chromosomes are not homologous, though they do have short regions of homology
Sex chromosomes (X and Y)
This is the physical location of a gene on a chromosome
Locus
What are two purposes of cell division?
Asexual reproduction and achieving multicellularity
This is one purpose of cell division, used by some unicellular organisms
Asexual reproduction
How often can E. coli divide?
Every 20 minutes
Prior to division, a bacterial cell does this
Replicates its chromosome
A bacterial cell divides into two daughter cells by this process
Binary fission
Does binary fission involve genetic contributions from two different gametes?
No
During binary fission, this protein recruits other proteins to create a new cell wall
FtsZ protein
Dividing eukaryotic cells progress through a series of stages known as this
The cell cycle
What three stages make up interphase?
G1, S, G2
In actively dividing cells, G1, S, and G2 stages are collectively known as this
Interphase
Can cells remain in the G0 phase for long periods of time?
Yes
A cell in the G0 phase in this state
Quiescent
Adult nerve cells are an example of this type of cell that is in a permanently quiescent state
Terminally differentiated cell
During this phase of cell division, the cell prepares to divide
G1 phase
This is the point at which a cell is committed to a cell division pathway.
Restriction point
During this phase of cell division, chromosomes are replicated
S phase
What is the term for the two copies of a replicated chromosome?
Chromatids
Chromatids are joined here to form a pair of sister chromatids
Centromere
What is another term for sister chromatids?
Dyad
This is made up of proteins attached to the centromere
Kinetochore
This is another term for a single chromatid
Monad
At the end of this phase, a cell has twice as many chromatids as it has chromosomes in the G1 phase
S phase
How many distinct chromosomes does a human cell have in the G1 phase?
46
How many pairs of sister chromatids does a human cell have at the end of the S phase?
46
In the G1 phase and late in the M phase, the term chromosome refers to the equivalent of this
One chromatid
In G2 and early in the M phase, the term chromosome refers to this
A pair of sister chromatids joined at the centromere
During this phase, the cell accumulates the materials that are necessary for nuclear and cell division
G2
Mitosis occurs in this phase of cell division
M phase
What is the primary purpose of mitosis?
To distribute replicated chromosomes to two daughter cells
What are the five phases of mitosis?
- Prophase; 2. Prometaphase; 3. Metaphase; 4. Anaphase; 5. Telophase
During this phase of cell division, chromosomes decondense
Interphase
Sister chromatid pairs are not seen until this phase of mitosis
Prophase
This is the attachment point of the mitotic spindle
Centrosome
Microtubules of the spindle apparatus are formed by rapid polymerization of these
Tubulin proteins
What are the three types of spindle microtubules?
- Aster microtubules; 2. Polar microtubules; 3. Kinetochore microtubules
This type of spindle microtubule is important for positioning of the spindle apparatus
Aster microtubules
This type of microtubule helps to push the poles of the spindle apparatus away from each other
Polar microtubules
This type of microtubule attaches to the binding part of the centromere of each individual chromosome
Kinetochore microtubule
What three things occur during prophase?
- Nuclear envelope dissociates into small vesicles; 2. Chromatids condense into more compact structures; 3. Centrosomes begin to separate
What four things occur during prometaphase?
- Spindle poles form; 2. Spindle apparatus forms; 3. Kinetochore microtubules grow from the two poles; 4. The two kinetochores on a pair of sister chromatids are attached to kinetochore microtubules on opposite poles
What two things occur during metaphase?
- Pairs of sister chromatids align themselves along a plane; 2. Each pair of chromatids is attached to both poles by kinetochore microtubules
This is the plane along which sister chromatids align themselves during metaphase
Metaphase plate
What two things occur during anaphase?
- The connection holding the sister chromatids together is broken; 2. Each chromatid (now an individual chromosome) is linked to only one pole
Do kinetochore microtubules lengthen or shorten during anaphase?
Shorten
Do polar microtubules lengthen or shorten during anaphase?
Lengthen
What two things occur during telophase?
- Chromosomes reach their respective poles and decondense; 2. Nuclear membrane reforms into two separate nuclei
In most cases, mitosis is quickly followed by this process
Cytokinesis
This is formed during cytokinesis in animal cells
Cleavage furrow
This is formed during cytokinesis in plant cells
Cell plate
What does mitosis/cytokinesis ultimately produce?
Two daughter cells with same number of chromosomes as mother cell
Are the two daughter cells that result from mitotic cell division genetically identical to each other?
Yes
Mitosis ensures this remains from one cell to the next
Genetic consistency
The development of this relies on the repeated process of mitosis and cytokinesis
Multicellularity
This is a common way for eukaryotic organisms to produce offspring
Sexual reproduction
In sexual reproduction, are parents diploid or haploid?
Diploid
In sexual reproduction, are gametes diploid or haploid?
Haploid
In sexual reproduction, gametes fuse with each other during this process to create a new diploid individual
Fertilization
Are gametes 1n or 2n?
1n
Are human diploid cells 1n or 2n?
2n
How many chromosomes does a human gamete have?
23
During this process, haploid cells are produced from diploid cells
Meiosis
Both mitosis and meiosis begin after a cell has progressed through this phase of the cell cycle
Interphase
What are the two divisions of meiosis?
Meiosis 1 and Meiosis 2
Each meiotic division is subdivided into these five parts
- Prophase; 2. Prometaphase; 3. Metaphase; 4. Anaphase; 5. Telophase
What are the five stages of prophase 1 of meiosis?
- Leptotene; 2. Zygotene; 3. Pachytene; 4. Diplotene; 5. Diakinesis
What happens during the leptotene stage of meiosis 1 prophase?
Replicated chromosomes condense
What happens during the zygotene stage of meiosis 1 prophase?
Synapsis begin to form a bivalent
What happens during the pachytene stage of meiosis 1 prophase?
A bivalent forms and crossing over occurs
What happens during the diplotene stage of meiosis 1 prophase?
Synaptonemal complex dissociates
What happens during the diakinesis stage of meiosis 1 prophase?
Nuclear membrane breaks apart, ending prophase 1
Meiosis 1 is followed by what two events?
Cytokinesis and then meiosis 2
What is the primary difference between meiosis 2 and mitosis?
Meiosis 2 begins with half the chromatids of mitosis
How many diploid daughter cells does mitosis produce?
2
How many haploid daughter cells does meiosis produce?
4
Does mitosis produce genetically identical daughter cells?
Yes
Does meiosis produce genetically identical daughter cells?
No
This is the process of making haploid gametes
Gametogenesis
Some simple eukaryotic species are this, meaning they produce morphologically similar gametes
Isogamous
What are two examples of isogamous eukaryotes?
Many species of fungi and algae
Most eukaryotic species are this, meaning they produce morphologically different gametes (sperm and egg)
Heterogamous
This is the production of sperm
Spermatogenesis
What two cells are produced by the mitotic division of a diploid spermatogonial cell?
A spermatogonial cell and a primary spermatocyte
Which of the two cells mitotically produced by a spermatogonial cell progresses through meiosis 1 and 2?
Primary spermatocyte
What are the two components of a sperm cell’s structure?
Flagellum and head
The head of a sperm cell contains this
Haploid nucleus
The head of a sperm cell is capped by this
Acrosome
The acrosome of a sperm cell contains these to enable the sperm to penetrate the protective layers of the egg
Digestive enzymes
This is the production of egg cells
Oogenesis
Early in development, these produce diploid primary oocytes
Diploid oogonia
In humans, how many primary oocytes are produced per ovary before birth?
~ 1 million
Primary oocytes remain arrested in this phase until the female is sexually mature
Prophase 1
At sexual maturity, primary oocytes are periodically activated to progress through this process
Meiosis 1
How many cells per meiosis becomes an egg from a primary oocyte?
1
What two unequally sized haploid cells are produced by meiosis 1 of primary oocytes?
A large secondary oocyte and a small polar body
Which product of primary oocyte meiosis 1 enters meiosis 2?
Secondary oocyte
The secondary oocyte is released into this structure in the process of ovulation
Oviduct
What are the two products of secondary oocyte fertilization?
Haploid egg and second polar body
These two things fuse to create the diploid nucleus of a new individual
Haploid egg and sperm nucleus
Are the divisions in oogenesis symmetric or asymmetric?
Asymmetric
Divisions in oogenesis produce these, containing very little cytoplasm
Polar bodies
What are the two generations that plant species cycle between?
Gametophyte and sporophyte
This is the haploid generation of a plant
Gametophyte
This is the diploid generation of a plant
Sporophyte
Sporophytes go through meiosis to produce these haploid cells
Spores
Spores divide by this process to produce gametophytes
Mitosis
Sporophytes go through this process to produce haploid spores
Meiosis
In this type of plants, spores develop into gametophytes that have large numbers of cells
Simpler plants (i.e. mosses)
In this type of plants, spores develop into gametophytes that only have a few cells
Flowering plants
Where are gametophytes contained within sporophyte flowering plants?
Within flower structure
This plant generation is what we consider the ‘plant’ in flowering plants
Sporophyte
This sporophyte structure produces the male gametophyte
Anther
This sporophyte structure produces the female gametophyte
Ovary
How many microspores does the anther produce through meiosis?
4
Mitosis of microspores produces these two types of cell
Tube cell and generative cell
In flowering plants, the microspore differentiates into this
Pollen grain
How many megaspores does the ovary produce through meiosis?
4
How many of the four megaspores produced by the plant ovary degenerate?
3
The surviving megaspore produced by the plant ovary yields an embryo sac with how many cells?
7
Flowering plants have this type of fertilization
Double fertilization
In double fertilization, one sperm fertilizes the egg while a second sperm unites with the central cell to produce this
Endosperm
Double fertilization ensures the endosperm will only develop when this happens
When an egg cell has been fertilized
What are the two steps following fertilization in flowering plants?
- Ovule develops into seed; 2. Surrounding ovary develops into fruit that encloses one or more seeds
This theory describes how the transmission of chromosomes account for Mendelian patterns of inheritance
Chromosome theory of inheritance
The chromosome theory of inheritance resulted from what three lines of scientific inquiry?
- Analysis of trait transmission from parent to offspring; 2. Inquiry into material basis of heredity; 3. Microscopic examination of mitosis, meiosis and fertilization
What are the five fundamental principles of the chromosome theory of inheritance?
- Chromosomes contain the genetic material; 2. Chromosomes are replicated and passed from parent to offspring; 3. The nuclei of most eukaryotic cells contain chromosomes in homologous pairs; 4. During meiosis, each homolog segregates into one of two daughter nuclei and nonhomologous chromosomes segregate independently; 5. Each parent contributes one set of chromosomes to offspring
This Mendel’s law can be explained by the homologous pairing and segregation of chromosomes during meiosis
Mendel’s law of segregation
This Mendel’s law can be explained by the relative behavior of different chromosomes during meiosis
Mendel’s law of independent assortment
In many animal species, these play a role in sex determination
Chromosomes
In some reptiles and fish, sex is determined by this
Temperature
What are the sex chromosomes in some insect species?
Males X0 and females XX
This determines maleness in insects that use X0/XX
Ratio between X chromosomes and number of sets of autosomes
Birds and some fish use this sex chromosome designation
Males ZZ; Females ZW
Bees use this sex determination system
Haplodiploid sex determination
Are male bees haploid or diploid?
Haploid
Are female bees haploid or diploid?
Diploid
Male bees are also known as these
Drones
Male bees are produced from these
Unfertilized haploid eggs
Female bees make up these two classifications of bees
Worker and queen bees
Female bees are produced from these
Fertilized eggs
Which scientist confirmed the chromosome theory of inheritance?
Thomas Hunt Morgan
Thomas Hunt Morgan tried to induce mutations in this species in his studies
Fruit fly (Drosophila melanogaster)
What are three treatments done on fruit flies by Thomas Hunt Morgan?
- Rearing in dark; 2. X-rays; 3. Radium
Thomas Hunt Morgan studied the inheritance of this fruit fly trait in particular
White-eyed trait
