test 3 Flashcards
What is cell division?
- The ability of organisms to produce more of their own kind is the one characteristic that best distinguishes living things from nonliving matter.
What is genome
- A cell’s genetic information, packaged as DNA, is called its genome.
difference between chromatin, chromosome, and chromatid
- DNA molecules are packaged into chromosomes.
- Every eukaryotic chromosome consists of one long, linear DNA molecule associated with many proteins. the complex is referred to as chromatin.
Each duplicated chromosome consists of two sister chromatid
How are somatic cells and gametes different
Human somatic cells (all body cells except sperm and egg) have 46 chromosomes,
Human reproductive cells or gametes (sperm or eggs) have one set of 23 chromosomes
What are mitosis and cytokinesis
Mitosis, the division of the nucleus, is usually followed by the division of the cytoplasm
Cytokinesis usually starts during the later stages of mitosis, and the spindle eventually disassembles by depolymerization of microtubules.
Cytokinesis divides the cytoplasm
What are the phases of the cell cycle
G1 phase, S phase, G2 phase, and M phase (mitosis phase
What is the correct order for the phases of the cell cycle?
G1, S, G2, and then M (mitosis) phase
During what sub-phase of the cell cycle is DNA replicated
S phase (Synthesis phase) of Interphase
What is the kinetochore
a kinetochore, a specialized protein structure located at the centromere.
How is cytokinesis in an animal cell different from cytokinesis in a plant cell
In animal cells, cytokinesis occurs by a process called cleavage.
During telophase, vesicles from the Golgi apparatus move along microtubules to the middle of the cell, where they coalesce to form a cell plate.
Cell wall materials carried in the vesicles collect in the cell plate as it grows.
The plate enlarges until its membranes fuse with the plasma membrane at the perimeter.
The contents of the vesicles form new cell wall material between the daughter cells.
What are the stages of mitosis?
prophase, prometaphase, metaphase, anaphase, and telophase.
What happens to the chromosomes in each stage of mitosis
- As the chromosomes condense, the region where the chromatids connect shrinks to a narrow area, made up of two centromeres.
What is binary fission? Which organism uses binary fission?
cell division called binary fission,
How do cyclins and kinases controls the cell cycle?
Cyclins are proteins that regulate the cell cycle by activating cyclin-dependent kinases (CDKs
The kinases that drive the cell cycle are present at constant concentrations but require the attachment of a second protein, a cyclin, to become activated.
What is cancer
Cancer cells do not stop dividing when growth factors are depleted.
What is difference between a benign tumor and a malignant tumor?
If the abnormal cells remain at the originating site, the lump is called a benign tumor
A malignant tumor includes cells whose genetic and cellular changes enable them to spread to new tissues and impair the functions of one or more organs.
An individual with a malignant tumor is said to have cancer.
What is metastasis
What is metastasisCancer cells are abnormal in many ways
How do density-dependent inhibition and anchorage dependence differ between normal cells
and cancer cells
Cultured cells normally divide until they form a single layer on the inner surface of the culture container. If a gap is created, the cells will grow to fill the gap.
The binding of a cell-surface protein to its counterpart on an adjoining cell sends a growth-inhibiting signal to both cells, preventing them from moving forward in the cell cycle, even in the presence of growth factors.
To divide, the cells must be anchored to a substratum, typically the extracellular matrix of a tissue.
Experiments suggest that, like cell density, anchorage is signaled to the cell cycle control system via pathways involving plasma membrane proteins and elements of the cytoskeleton linked to them.
What is Genetics
Genetics is the scientific study of heredity and hereditary variation.
How are asexual reproduction and sexual reproduction different
Asexual reproduction is a method of reproduction that creates offspring that are genetically identical to a single parent
it involves the fusion of genetic material from two parents, creating offspring that are genetically unique
what is a clone?
clone, a group of genetically identical individuals.
What are homologous chromosomes?
Homologous chromosomes appear to be alike, but they may have different versions of genes, each called an allele, at corresponding loci
What is a karyotype? What are sex chromosomes versus autosomes
Images of the 46 human chromosomes can be arranged in pairs in order of size to produce a karyotype display
Sex chromosomes determines an individual’s sex. Human females have a homologous pair of X chromosomes (XX); males have one X and one Y chromosome (XY).
The other 22 pairs of chromosomes are called autosomes.
The occurrence of homologous pairs of chromosomes is a consequence of sexual reproduction.
What is meiosis
Meiosis is a type of cell division that produces gametes (sperm and egg cells) in sexually reproducing organisms.
How are diploid and haploid different?
Any cell with two sets of chromosomes is called a diploid cell and has a diploid number of chromosomes, abbreviated as 2n.
A cell with a single chromosome set is a haploid cell, abbreviated as n.
Any sexually reproducing species has characteristic haploid and diploid numbers of chromosomes.
What are the haploid and diploid numbers of chromosomes in humans
haploid number of chromosomes is 23
diploid number is 46
What are the common pairs of sex chromosomes (XX-female, XY-male) in humans
the female is XX and the male is XY
What is a zygote?
A zygote is a fertilized egg cell that contains all the genetic information needed to develop into an embryo and eventually a fetus:
How are mitosis and meiosis different
Gametes undergo the process of meiosis, in which the chromosome number is halved.
Human sperm or ova have a haploid set of 23 different chromosomes, one from each homologous pair.
Mitosis is a type of cell division that produces two identical daughter cells from a single parent cell
hat is a chiasma
Chiasmata hold homologs together as the spindle forms for the first meiotic division.
What are other names for a pair of homologous chromosomes?
homologs or bivalents
What are the stages of meiosis I and meiosis II
The first division, meiosis I, separates homologous chromosomes.
The second division, meiosis II, separates sister chromatids.
The four daughter cells at the end of meiosis have only half as many chromosomes as the original parent cell.
What is fertilization
The union of these gametes, culminating in the fusion of their nuclei, is fertilization.
Fertilization restores the diploid condition by combining two haploid sets of chromosomes.
Both sperm and eggs are haploid cells. What does that mean
“Haploid” means that both sperm and egg cells contain only one set of chromosomes
only 23
What are the definitions for synapsis, crossing over, independent assortment, and random
fertilization?
the fusion of chromosome pairs at the start of meiosis.
a genetic process that occurs when homologous chromosomes exchange genetic material during sexual reproduction
a genetic principle that describes how genes separate independently during the development of reproductive cells
a process in sexual reproduction where a sperm cell from a male parent and an egg cell from a female parent randomly unite to form an offspring
What is Gregor Mendel known as
father of modern genetics
What are Mendel’s first and second laws of Genetics?
The Law of Segregation
If the blending hypothesis were correct, the F1 hybrids from a cross between purple-flowered and white-flowered pea plants would have pale purple flowers.
Instead, the F1 hybrids all have purple flowers, just as purple as their purple-flowered parents.
The Law of Independent Assortment
Mendel’s first experiments followed only a single character, such as flower color.
All the F1 progeny produced in these crosses were monohybrids, heterozygous for one character.
A cross between two heterozygotes is a monohybrid cross.
Mendel identified the second law of inheritance by following two characters at the same time.
*In one such dihybrid cross, Mendel studied the inheritance of seed color and seed shape.
What are the components of a monohybrid versus a dihybrid cross
in a monohybrid cross, only one trait is being studied, while in a dihybrid cross, two traits are being studied simultaneously
What is a test-cross? What is a test cross used for?
a genetic experiment that determines the genotype of an organism by crossing it with a known genotype
What are the definitions for these terms?: genotype, phenotype, heterozygous, homozygous
an organism’s complete genetic makeup or the specific alleles or variants of a gene that an organism carries
the observable characteristics of an organism, such as its appearance, behavior, and development
A term that describes having two different versions of the same gene
a genetic term that describes when someone inherits the same versions of a gene from both parents
What are the exceptions to Mendel’s Laws
Incomplete dominance
Co-dominance
Pleiotropy
Nondisjunction
Linkage
Epistasis
What are some examples of recessive inherited disorder?
Cystic fibrosis.
Sickle cell disease.
Tay-Sachs disease.
What do the symbols on a human pedigree chart represent
a circle represents a female, a square represents a male, and a filled-in symbol (circle or square) indicates an individual affected by the trait being studied, while an open symbol represents an unaffected individual; a horizontal line connecting two symbols shows a mating pair, and vertical lines connect parents to their offspring, with siblings listed from left to right in birth orde
What are some examples of dominant inherited disorders?
Huntington’s disease, Marfan syndrome, achondroplasia, familial hypercholesterolemia, neurofibromatosis type 1, polycystic kidney disease (adult), Ehlers-Danlos syndrome, and hereditary hemorrhagic telangiectasia
What are the processes for fetal testing
Fetal testing can include a variety of processes, such as ultrasounds, blood tests, and other diagnostic tests
. What is Amniocentesis? What is Chorionic Villus Sampling
Amniocentesis and chorionic villus sampling (CVS) are both prenatal tests that can help diagnose genetic conditions in a fetus
What is the chromosomal theory of inheritance?
The chromosomal theory of inheritance states that chromosomes, which are structures within cells, are the carriers of genetic material and that the behavior of chromosomes during meiosis explains how genes are inherited according to Mendel’s laws
What are wild type versus mutant types? What is the difference between them
In genetics, the main difference between wild type and mutant types is that wild type is the phenotype that is most common in a natural population, while mutant is a phenotype that is less common
How do sex-linked (X-linked) genes impact males versus females
Males have one X chromosome, so any mutated gene on that X chromosome will cause a disease or condition. Males cannot pass X-linked traits to their sons, but they can pass them to their daughter
Females have two X chromosomes, so a mutated gene on one X chromosome usually won’t affect them. However, females can be affected by X-linked recessive disorders if both copies of the gene on their X chromosomes are mutated.
. What are the components of a sex-linked cross
mating a male with two recessive genes with a female that has the dominant form of the gene. The components of a sex-linked cross
What are three examples of sex-linked recessive disorders in humans
red-green color blindness, hemophilia A, and Duchenne muscular dystrophy
What is nondisjunction
the failure of chromosomes or chromatids to separate properly during cell division
What are the terms for abnormal chromosome numbers?
The term for abnormal chromosome numbers is aneuploidy. This refers to a condition where an individual has an extra or missing chromosome, resulting in an abnormal chromosome coun
. What are the terms for alterations of chromosome structure? What does each term mean?
Alterations of chromosome structure are called “chromosomal aberrations” and include terms like deletion (a piece of chromosome is missing), duplication (a piece of chromosome is copied extra), translocation (a piece of one chromosome moves to another), and inversion (a piece of chromosome flips and reattaches backwards).
. What are examples of human disorders due to chromosomal alterations
Down Syndrome.
Fragile X Syndrome.
Angelman Syndrome.
Smith-Lemli-Opitz Syndrome.
Rett Syndrome.
