Question | Answer |
Before cells are able to reproduce, there must be a... | Division of the nucleus and its DNA and cytokinesis |
Mitosis is used by muliticelled organisms for... | growth, development, and repair |
Mitosis has what cells? | Somatic cells |
Meiosis occurs in which somatic cells? | Germ cells |
What do germ cells divide into? | Gametes |
Each threadlike chromosome is duplicated to form... | Two sister chromatids held together by a centromere |
Humans somatic cells contain __ chromosomes | 46 |
Which cells are diploid? | Somatic cells |
How many chromosomes do diploid cells have? | 2 |
What are Gametes? | Egg and sperm |
Which cell is haploid? | Gametes |
How many chromosomes do haploid cells have? | 1 |
Most of the cells existence is spent in... | Interphase |
During interphase.... | the cells mass increases and the DNA is duplicated |
During G1 phase.... | carbohydrates, lipids, and proteins for a cells use and for export are assembled. |
During S phase... | the cell copies it DNA and synthesizes proteins |
During G2 phase... | proteins that will drive mitosis to completion are produced. |
What are the 4 stages of mitosis? | Prophase,Metaphase, Anaphase, and Telophase. |
The spindle apparatus does what? | moves the chromosomes. |
What extends from the 2 poles of a cell and overlap at the cells equator? | Microtubules. |
Chromosomes become visible rodlike units with each having 2 sister chromatids is what stage? | Prophase. |
The centromere is | a docking site for the spindle microtubules on each chromatid. |
Microtubules are composed of.. | tubulins |
The nuclear envelope begins to disintegrate in which stage? | Prophase |
The centrioles are moved by the microtubules to the opposite poles of the cell in which phase? | Prophase. |
Nuclear membrane breaks up completely in which stages? | Between prophase and metaphase. |
Sister chromatids become oriented toward opposite poles in what stage? | Metaphase. |
What stage takes place when all the chromosomes are aligned at the cells equator? | Metaphase |
At metaphase sister chromatids are at | Max. condensation |
Sister chromatids separate and move toward oppostite poles during which stage? | Anaphase |
When the two daughter chromosomes of each original chromatid pair arrive at opposite poles, which stage is beginning? | Telophase |
The nuclear envelope reforms during | Telophase |
When each daughter cell has the same number of chromosomes as the parent cell.... | Telophase is done and mitosis is complete. |
The flexible plasma membrance of animal cells can be squeezed in the middle to separate the two daughter cells..what is this called? | cleavage or furrowing |
Plant cells cannot be pinched in two because.... | the rigid cell wall |
Organisms that reproduce asexually rely on | chromosome duplications and mitotic cell divisions |
Somatic germ cells go through a type of cell division called | meiosis and cytokinesis to produce gametes. |
Meiosis begins with diploid germ cells(2n=46 in humans) and produces | haploid gametes (n=23) |
In 2n cells there are 2 chromosomes of each type called | homolugous chromosomes. |
During meiosis, homologous chromosomes | line up, even unequally matched sex chromosomes |
Meiosis produces gametes that have | one of each pair of homologous chromosomes. |
Meiosis has how many series of divisions | 2 |
During meiosis I, homologous chromosomes pair and | cytokinesis follows and each daughter cell receives a haploid number of chromosomes. |
In meiosis II, the sister chromatids of each chromosome | separate; cytokinesis follows resulting in 4 haploid cells. |
In meiosis prophase 1, nonsister chromatids exchange segments in a process called | crossing over |
After crossing over, the non sister chromatids begin to separate but remain attatched by | chiasmata |
In meiosis metaphase I, homologous chromosomes... | randomly line up at the spindle equator. |
During meiosis anaphase I, homologous chromosomes... | separate into two haploid cells. |
In males, meiosis and gamete formation are called | spermatogenesis |
In females, meiosis and gamete formation are called | oogenesis |
Random alignments at metaphase I lead to | millions of maternal and paternal chromosomes in each gamete |
Chromosomes are moved by the | spindle apparatus |
Observable traits, like five fingers on each hand, are the result of | genetic expression |
The first person to systematically pursue the questions of genetic | Gregor Mendel |
Units of information about specific traits. | Genes |
Each gene has a _______ on a chromosome | locus |
What cells have two genes for each trait on a homologous chromosome? | Diploid cells |
Various molecular forms of a gene for the same trait are | Alleles |
Occurs when offspring inherit identical alleles | true-breeding |
Non-identical alleles produce | hybrid offspring |
When both alleles are the same, this is called | Homozygous condition |
If the alleles differ then its | Heterozygous condition |
When one allele is dominate A and the other is recessive a its... | heterozygous |
When both alleles are dominate AA its.... | Homozygous dominant |
aa= | homozygous recessive |
Aa= | heterozygous |
The sum of the genes are the | genotype |
Genes that are expressed by what you observe are the | phenotype |
P= | Parental generation |
F1= | first-generation offspring |
F2= | second-generation offspring. |
What has two parents that are true-breeding for contrasting forms of a trait | Monohybrid |
Mendel disproved the | blending model |
What theory states that 2n organisms inherit two genes per trait located on pairs of homologous chromosomes | The Mendelian theory |
Chromosomes segregate independently of each other and give the same F2 phenotypic ratio Mendel observed are... | non homologous |
A dominant allele that cannot completely mask the expression of another | incomplete dominance |
A case where both dominant alleles are expressed in heterozygotes. | Codominance |
Whenever more than two forms of alleles exist at a given locus is | a multiple allele system |
Alleles at one location that can have have effects on two or more traits is called | termed pleiotropy |
One gene pair can influence other gene pairs, with the combined activities producing some effect on the phenotype..this is called.. | epistasis |
Most of the chromosomes are of the same quantity and type in both sexes and are called | Autosomes |
Sex chromosomes 92 in humans) | determine gender |
What chromosomes do females have? | two X chromosomes |
What chromosomes do males have? | one x and one y |
Chromosomes that are visualized in a lab preparation is called | a karyotype |
A term applied to a genetic condition that is a deviation from the usual, or average, and is not life threatening. | Genetic abnormality |
Used to describe conditions that cause medical problems. | Genetic disorder |
Applied to those instances where a persons altered genes increase susceptibility to infection | Genetic disease. |
The dominant allele is nearly always expressed | autosomal dominant |
Either parent can carry the recessive allele on an autosome | autosomal recessive |
This occurs when a gene sequence is in excess of the normal amount | duplication |
This alters the position and sequence of the genes so that gene order is reversed | inversion |
A condition in which the gametes or cells of an affected individual end up with one extra or one less chromosome than is normal | Aneuploidy |
The presence of three or more of each type of chromosome in gametes or cells | Polyploidy |
Anaphase I or anaphase II frequently results in a change in chromosome number due to | nondisjunction |
Consists if a single layer of cells | Simple epithelium |
Supports epithelia and organs and surrounds blood vessels and nerves | Loose connective tissue |
Could be found in tendons and ligaments | Dense connective tissue |
What contains chondrocytes and a dense array of fibers in a jelly like ground substance? | Cartilage |
What stores mineral salts, produces blood cells, and provides spaces for its own living osteocytes | Bone tissue |
Cells that are specialized for the storage of fat, which can be used as an energy reserve and as cushions to pad organs | Adipose tissue |
Transports oxygen, wastes, hormones, and enzymes | blood |
contracts in response to stimulation | muscle tissue |