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14bio5785
CU intro to bio: lecture 14
| Question | Answer |
|---|---|
| Multicellular eukaryotes are made of two fundamental cell types... what are they? | Somatic cells and germ cells |
| Somatic cells are? | the cells that form the building blocks of ,the body (AKA body cells). They cannot produce gametes. |
| Germ cells | .are cells capable of reproducing themselves or producing gametes (eggs and sperm). These are only found in organisms that reproduce sexually, and germ cells are located in the gonads (ovaries and testicles). |
| Where are germ cells produced in humans? Is it different for males and females? | Germ cells are found in sexual reproducing organisms, in their gonads. It is different for males and females because the male's germ cells are created in the testis and the female's germ cells are created in the ovaries. |
| ToF: Germ cells contain half the genetic code of that particular individual, necessitating reproduction. | FALSE:Both somatic and germ cells contain the entire genetic code of that particular individual.Mp |
| Reproduction begins with what? | reproduction begins with the division of single cells. |
| In order for a new generation of cells to start up its own operation, what does it need? | It must recieve a copy of all parental DNA and enough cytoplasmic machinery to start up its own operation. |
| Mitosis and Meiosis are what? | Eukaryotic nuclear division mechanisms that lead to the distribution of DNA to new nuclei in forthcoming daughter cells |
| Cytokineses - | -is the mechanism by which daughter cells receive cytoplasmic machinery. |
| Mitosis | .is the nuclear division mechanism that maintains the chromosome number. Somatic cells divide by mitosis |
| ToF: Somatic cells only divide by mitosis. | TRUE. |
| Meiosis - | .is the nuclear division mechanism that reduces the chromosome number to half. Germ cells are the only type of cells that can undergo meiosis, because they are the only cells that form gametes. |
| ToF - Germ cells only divide by meiosis. | FALSE: germ cells produce gametes via meiosis. But they can also produce more germ cells via mitosis, just as a somatic cell does |
| A chromosome is? what is its shape? | ;is a complete molecule of DNA and its associated histones. A chromosome is a double-stranded molecule |
| Prior to division, each chromosome is .....? | Duplicated |
| The original chromosome and its new clone are joined together at what area on the Chromosome? | the centromere |
| What are sister chromatids? | The' original chromosome and its new clone are joined together at the centromere. They are referred to as sister chromatids |
| The centromere | is the region where the chromosome will attach to microtubules during nuclear division. |
| The Cell Cycle.... represents what? | The cell cycle is a recurring sequence of events that extends from the time of a cell's formation until its division is completed����� |
| Most of a cells existence occurs in what phase? what percentage? | interphase, about 90% |
| Durring interphase what happens? | the cell's mass increases (G1), the DNA is doubled (S), and the cytoplasmic components approximately double in number (G2 |
| ToF: Some cells are arrested in interphase and never divide again. | True, ex brain cells |
| What are homologous chromosomes? | It is a pair of identical chromosomes |
| What is the difference between Sister Chromatids and homologous pairs of chromosomes? | Sister chromatids are two clones attached at the centromere. Sister chromatids = 1 chromosome A homologous pair of Chromosomes, is just pairs of identical chromosomes in a cell. |
| How many chromosomes/pairs do somatic cells contain in humans? Elephants? | Humans = cells contain 46 chromosomes (23 homologous pairs) Elephants = 56 chromosomes in each of their somatic cells (28 homologous pairs) |
| How many chromosomes/pairs do germ cells contain in humans? Elephants? | Humans= 23 chromosomes and no homologous pairs in germ cells Elephants = Have 28 chromosomes and no homologous pairs |
| What is the difference between Haploid and diploid? What is the significance of 2n, 1n, or etc? | A haploid cell =1n: has no homologous pairs of chromosomes. these are gametes diploid cell =2n: this represents a homologous pairs of chromosomes in a cell |
| how ar chromosomes moved ? | they are moved by spindle apparatus composed of microtubules . |
| Microtubules? | these (components of the cytoskeleton) extend from two "poles" established by the centrioles, once the centrioles have moved to opposite ends of the cell.: |
| WHat are the four sections of Mitosis? | Prophase, Metaphase, Anaphase, and Telephase PMAT |
| In prophase | Chromosomes begin to condense: and the centriols start moving toward opposite poles. spindles form |
| What is the common representation of duplicated homologous pairs of chromosomes? | [ )( )( ] or [XX] (not the same as 23 chromosomeal pairs) which are represented as |
| Metaphase | The nuclear envelope breaks up in between the meta and pro All chromosomes become aligned single file at the cell's equator. Each of the sister chromatids are oriented toward opposite poles |
| how doe the sister chromatids orient? | Spindle fibers and kinetochores interact to orient the chromatids |
| what is the Kinetochore? | in the centromere region of each chromatid is the place of attachment to several spindle microtubules. |
| Anaphase: | Sister chromatids are separated and start moving toward opposite poles. Now each chromatid is an independent chromosome |
| How do the microtubules affect the anaphase? | Microtubules attached to kinetochores shorten as chromosomes approach poles. Other microtubules at the spindle poles elongate to push spindle poles apart |
| Telophase ? | Starts when the chromosomes (used to be sister chromatids) reach the poles. The nuclear envelope reforms from the fusion of small vesicles Mitosis is complete at the end of telophase |
| Cytokinesis: | In animal cells, contractile microfilaments at the cleavage furrow pull the plasma membrane inward Plant cells form a cell plate (cellulose) that separates the two new cells. |
| The cell cycle has built-in checkpoints that correct problems before the cylce continues, what are these checkpoints? | They are called Checkpoint genes that are made by protein |
| when a checkpoint mechanism fails.... what happens? | it loses control over its replication cycle. |
| Mutated checkpoint genes are associated with what problem? | Tumor formation, could be hereditary. |
| tumors? | or neoplasms, are abnormal masses of cells that have lost control over their growth and cell division. These can be benign or malignant |
| Benign growths | pose no threat to the body and typically remain in their home tissue |
| Malignant growths | growths are known as cancers. These can pose a significant threat to the body, and are known to grow beyond their home tissue. |
| Metastasizing | .The process by which malignant cells spread to a different part of the body is called |
| Charcteristics of Malignant growths (cancers) | Cancers are abnormally growing and dividing cel |
| Metastasis | Cells have a weakened capacity for adhesion and may break away to move to other sites in the body. |
Created by:
jseekins
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