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97 Cards in this Set
- Front
- Back
- 3rd side (hint)
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How does the life cycle of a cell occur? |
From 1 cell division to the next |
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What is the term for new cells? What function do they need to carry out? |
Daughter cells; must have same function as the original (parent cells) |
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Is it necessary to replicate genetic material (aka DNA) for cell replacement? |
Yes, and it will be passed on to new cells |
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What are chromosomes? Where are they found, what do they consist of? |
The organization of genetic material. (Length of DNA) Found in nucleus. Consists of DNA and associated proteins. |
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What is the form of chromosomes? (Aka why is it the shape it is) Does it form anything? |
It wraps around proteins (histones) to form chromatin (uncoiled) |
A double helix |
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What holds sister chromatids together? |
Centromere |
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Histones? |
Highly organized arrangement of protein. DNA compacts the material within the cell |
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For humans, how many chromosomes does the Somatic (body cells) have? And names for each? |
Has 23 pairs overall. Chromosomes 1-22 ~ autosomes Chromosomes 23 ~ Sex chromosomes |
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Originally, how did the homologous chromosomes come to be? Are the chromosomes replicated at this point? |
One from egg, other from sperm. No. |
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Replicated cells are... (Draw out shape) |
2 sister chromatids Joined. |
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Unreplicated cells are.... |
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Are homologous chromosomes identical to one another? Why? |
No, BC although they might have the same gene, they might have a different allele. (Form) |
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Example for homologous chromosomes? |
Two genes: the eye color The alleles: blue vs brown |
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What are genes |
A specific sequence of DNA |
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What is locus |
At the specific location |
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Are Sex chromosomes homologous? |
They may or may not, depending on gender.
Ex: (female XX) (male XY) |
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What are diploid? Written as.... |
When chromosomes are in pairs. Written as 2n. |
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For diploid 2n, n represents? |
The number of chromosomes in gametes |
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What are haploids? Written as? |
When chromosomes ( ex in gametes) are arranged as singles.
Written as n. |
Humans: 2n=46 _________n=23 |
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What are polypoids referring to? |
Species that have chromosomes with arrangements more than pairs |
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Example of chromosomes polypoids? |
Tetraploid (4s) and octoploids (8s) |
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What are the 3 phases in a cell's life and brief description of each? |
Interphase (most of life cycle, just being a cell) , mitosis (division of genetic material and nucleus to 2), cytokinesis (division of everything else; cytoplasm and organelles to 2) |
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3 phases of interphase? |
G1, S, G2 |
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What happens in G1 of interphase? |
Cell grows quickly. Chromatin is not visible. Not much is known about this phase. |
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What happens in S phase of interphase? |
DNA replication. Centromere joins 23 identical pairs of sister chromatins.
Hence, synthesis or S phase. |
What replicates? |
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What happens in G2 phases of interphase? |
Cell continues to grow, preparing for division. The # of organelle increases. |
Prepare for prophase |
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PMAT means |
Prophase, Metaphase, Anaphase, Telophase |
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What happens in prophase of mitosis? (Part 1) |
Chromosomes become visible as they shorten & condense. Nuclear membranes disappears. |
The first phase of mitosis. (Prophase= prepare) What condenses? Anything form/disappear? |
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What happens in prophase (part 2) |
Centrioles move to opposite ends of cell. (Forms spindle) Fibres form and attach to centromere (acting as guides) |
Centrioles.....? What forms? Why? |
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What happens in Metaphase? |
Spindle fibres guide the chromosomes (sister chromatids) to the middle of the cell (facing opposite sides) |
2nd phase M=middle |
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What happens in Anaphase? |
Centeomeres divide/spilt apart. Sister chromatids are pulled towards opposite ends of the cell.
Now the sister chromatids are called chromosomes. |
3rd phase A=away |
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What happens in telophase? |
Chromosomes start to lengthen and unwind. Spindle fibres dissolve and nuclear membrane reforms around chromatin.
Nucleus is now split. |
Final phase. Steps are opposite to prophase. |
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(general) What happens in cytokinesis? What forms? |
The division of cytoplasm and organelles. 2 new daughter cells are formed and identical to parent cell. |
Follows telophase. |
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Cytokinesis for plants? |
A new cell plate forms |
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Cytokinesis for animals? |
The membrane pinches off and in the middle |
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karyotype |
a particular set of chromosomes that an individual pocess |
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homologous chromosomes |
pairs of chromosomes that contain the same gene sequences but with different alleles |
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sister chromatids are? |
2 chromatids that are genetically identical and attached by centromere |
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diploids |
a cell that contains a pair of every chromosome, called 2n |
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purpose of mitosis |
to generate identical cells |
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what are some things homologous chromosomes have in common and difference? |
length, centromere location, banding pattern difference: alleles of same genes |
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What does meiosis do? |
Produce haploid cells from diploid cells |
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What is meiosis? Results in? (Key outcomes) |
It's a cell division that produces daughter cells with 1/2 the # of chromosomes as parent cell.
Since there's 2 nuclear divisions, it results in 4 daughter cells. |
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Why do parents have offspring that are different from others? |
Because cells produced though meiosis have different gene combinations. |
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What happens in meiosis 1? |
Reduction Division. Cells are haploid at the end of meiosis 1, from the separation of homologous pairs. |
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What happens in meiosis 2? |
Separation of sister chromatids.
(No change in #) |
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What is synapsis? |
When each pair of homologous chromosomes align |
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What is a tetrad? |
A pair of homologous chromosomes that has 4 chromatids |
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What happens in prophase 1 of meiosis? |
Synapsis. Each chromosome would have 2 sister chromatids that are identical. Non sister chromatids cross over and exchange DNA/Genetic info. |
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Metaphase 1 of meiosis? (occurrence and picture description) |
Homologous pairs of chromosomes line up at equator. (2 on opposite sides; pole facing is completely random) |
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homologous pairs are... |
tetrads |
T_____ |
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Anaphase 1 of Meiosis? |
Homologous pairs of chromosomes separate and move to opposite poles (segregation) |
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What are cells at the end of anaphrase 1? |
haploid cells |
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segregation is when |
chromosome tetrads separate and move to opposite poles |
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What happens in Telophase 1? |
nuclear membrane develops, cytoplasm divides 2 haploid daughters have been made; marking end of meiosis 1 |
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entering meiosis 2, daughter cells contain ________ |
replicated chromosomes |
R____ C_____ |
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What happens in Meiosis 2? (General) |
same process as mitosis; resulting in 4 genetically different daughter cells (from parent cells and one another) |
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prophase 2 |
membrane disappears |
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metaphase 2 |
line up at equator |
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anaphase 2 |
splits sister chromatids |
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telophase 2 |
nuclear membrane and nucleolus reappear, chromosomes uncoil from chromatin |
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what does meiosis have that mitosis doesn't? |
synapses, homologous recombination, reduction division |
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What is the outcome of meiosis? |
formation of genetically distinct gametes |
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During Metaphase 1, chromosomes line up in ___________ along the _________ |
homologous pairs, equator |
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In independent assortment, the pairs in which chromosome fibres faces each pole is _________ of every other pair of _______ |
independent/random; homologous chromosomes |
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3 pairs of chromosomes can make ___ genetically different gametes |
8 |
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homologous chromosomes align during _______, which __________ exchange __________ (does not always happen) |
prophase 1, non-sister chromatids, chromosomes |
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how do chromosomes contain some genes from mom and other from dad? |
crossing over |
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what is non-disjunction |
a type of chromosomal mutation that results when chromosomes do not separate normally |
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when can non-disjunction occur |
during anaphase 1/2 when homologous pair of chromosomes don't separate. |
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extra chromosome expression |
n+1 |
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missing chromosome expression |
n-1 |
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result from non-dysjunction during anaphase 1 |
results in 2 gametes with correct # of chromosomes and 2 gametes with the incorrect # of chromosomes |
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trisomy is |
having an extra chromosomes |
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monosomy is |
missing a chromosome |
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Parent cells are germ cells that are called ________ |
Spermatogonium (ia) and oogenium (germ cells) |
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What produce primary spermatocytes |
Spermatogonium |
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(male) What stimulates what at Puberty? What gets produced? |
Testrosterone simulates meiosis 1. As a result, the primary spermatocytes will make 2 secondary spermatocytes (haploids) |
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Each secondary spermatocytes undergoes ________, forming _________ spermatids |
Meiosis 2, 4 haploids spermatids |
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Spermatids mature to _________ |
Sperm cells (all equal in size and functional) |
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For female, how are primary oogcytes come to existence? |
They are formed prior to birth and stopped in prophase 1 until Puberty |
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What does the primary oogcyte undergo after Puberty? |
Meiosis 1 (each month) |
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When the oogcyte undergoes meiosis 1, does the cytoplasm develop equally and result? |
No. The cell that gets most of cytoplasm is the secondary oogcyte, and the other a polar body. |
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Does the polar body usually degenerate? |
Yes |
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Does the secondary oogcyte that undergoes meiosis 2 divide equally? |
No |
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What is the cell that receives the cytoplasm called? And the other? |
Cytoplasm received: ovum (mature egg) Not received: polar body |
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Oogenisis and spermatogenesis both involve.... |
Meiosis |
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2 types of twins |
Identical and fraternal |
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What is identical twin originate from? Possibilities? |
When the zygote Splits into 2, then developing into an embryo. Can be XX XX, XY XY, but cannot to XX XY |
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What is fraternal twins from possibilities? |
When more than 1egg is fertilized. Can be XX XX, XY XY, XX XY |
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What is asexual reproduction? |
A type of mitosis; when a parent organism produces genetically identical offspring |
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What is sexual reproduction? |
A type is meiosis. It produces genetically distinct offspring though fertilization of genetically distinct gametes. |
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What is alteration of generations? |
Life cycle of a plant that alternates b/w a diploid sporophyte (2n) and haploid gametophyte (n) |
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How do sporophytes produce haploid spores? |
Though meiosis, which develops without fertilization. It grows into a plant a gametophyte |
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What do gametophytes produce? |
Male and female gametes which fuse at fertilization to make another sporophyte. |
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Result of spermatogenesis? (Sperms) |
All spermatids have 23 chromosomes, equal in size |
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Are polar body functional? Why do this happen? |
No, BC unequal division of cytoplasm |
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