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60 Cards in this Set
- Front
- Back
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DNA |
hereditary info of all living cells |
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Where is DNA contained? |
one or more chromosomes |
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Nucleotides |
long chain of _____ that create DNA; consist of a phosphate, deoxyribose, and a base (ACGT) |
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double helix |
two long strands of nucleotides wound around each other |
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genes |
units of inheritance; segments of DNA |
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after cell division, daughter cells ________ |
grow and develop or differentiate |
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differentiate |
becoming specialized for specific functions (contraction, fighting infection, producing digestive enzymes, etc) |
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stem cells |
an undifferentiated cell capable of dividing and giving rise to one or more distinct types of differentiated cells |
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sexual reproduction |
occurs when offspring are produced from gametes from two adults; two haploid gametes fuse to form diploid zygote |
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gametes |
sperm and eggs |
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asexual reproduction |
reproduction that does not involve the fusion of haploid gametes (budding) |
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DNA of prokaryotic cell is contained where? |
circular chromosome |
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first step of binary fission |
circular DNA double helix is attached to plasma membrane at one point |
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second step of binary fission |
DNA replicates and 2 DNA double helices attach to plasma membrane at nearby points |
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third step of binary fission |
new plasma membrane is added between attachment points, pushing them further apart |
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fourth step of binary fission |
plasma membrane grows inward at middle of cell |
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fifth step of binary fission |
parent cells divides into two daughter cells |
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where are eukaryotic chromosomes located? |
within a membrane-bound nucleus |
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have multiple chromosomes |
eukaryotic cells |
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contains single DNA double helix |
each human chromosome |
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protein DNA is wound around |
histones (further coil to reduce length of DNA) |
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each gene occupies a specific space, or _____ on a chromosome |
locus |
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how many telomeres in one chromosome? |
two |
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how many centromeres in one chromosome? |
one |
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telomere |
ends of a chromosome |
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centromere |
holds two daughter DNA double helices together after replication and is the attachment site for microtubules |
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duplicated chromosome |
consists of two identical DNA double helices, now known as sister chromatid (attached to each other at centromere) |
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karyotype |
preparation showing number, sizes, and shapes of all the chromosomes within a cell |
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homologous chromosomes (or homologues) |
chromosomes that contain the same genes |
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diploid |
cells with pairs of homologues |
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mutation |
a change in the base sequence of DNA in a gene; often used to refer to a genetic change that is significant enough to alter the appearance or function of the organism |
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a human cell has _____ pairs of chromosomes |
23 |
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a human cell has a total of ____ chromosomes |
46 |
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autosomes |
a chromosome that occurs in homologous pairs in both males and females and that does not bear the genes determining sex |
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sex chromosomes |
either of the pair of chromosomes that usually determines sex of an organism (X and Y chromosomes in mammals) |
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haploid |
cells that contain only on of each type of chromosome |
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during interphase, _____.... |
the cell acquires nutrients from environment, grows, and duplicates its chromosomes |
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majority of time is spent in ______ |
interphase |
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G1 |
1) cell grows in size 2) cell specializes to perform function 3) cell is sensitive to signals that help it decide whether to divide |
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"S" phase is entered when |
cells decides to divide |
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"S" phase |
DNA synthesis occurs |
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G2 phase |
cell grows and synthesizes proteins needed for division |
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mitotic cell division |
consists of nuclear division (mitosis) followed by cytoplasmic division (cytokinesis) |
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where does mitosis get its name from? |
mitosis comes from Greek word "thread"; during mitosis, chromosomes condense and appear thread-like when viewed through a microscope |
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cytokinesis |
cytoplasm is divided by two daughter cells |
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the mechanism of asexual reproduction in eukaryotic cells |
mitosis |
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cytokinesis typically occurs during _____ |
telophase |
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first phase of mitosis |
prophase |
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prophase steps |
1) duplicated chromosomes condense 2) spindle microtubules form 3) chromosomes are captured by spindle microtubules |
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when mitosis begins, each chromosome already consists of 2 _______ |
sister chromatids attached at centromere |
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nucleolus disappears |
during prophase |
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second stage of mitosis |
metaphase |
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microtubules lengthen or shorten until each chromosome lines up with equator of cell (one kinetochore facing each pole) |
during metaphase |
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third stage of mitosis |
anaphase |
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sister chromatids separate, becoming daughter chromosomes. one of two daughter chromosomes moves to each pole of cell. polar microtubules grab onto one another at equator, and then lengthen and push on each other |
during anaphase |
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final stage of mitosis |
telophase |
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spindle microtubules disintegrate and nuclear envelope forms around chromosomes. chromosomes revert to extended state and nucleoli begin to form. |
during telophase |
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cytokinesis in animal cells |
microfilaments attached to plasma membrane form ring around equator of cell, which contracts and constricts cell's equator. two daughter cells eventually formed |
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cytokinesis in plant cells |
carb filled vesicles meet at cell's equator between two nuclei. vesicles fuse producing cell plate. when enough fusion has occurred, edges of cell plate merge with plasma membrane |
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following cytokinesis, eukaryotic cells enter ______ |
G1 of interphase |
