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48 Cards in this Set
- Front
- Back
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all cells are derived
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from preexisting cells
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cell division
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is the process by which cells produce new cells
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cell division differs in
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prokaryotes and eukaryotes
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some tissues must be repaired often like:
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skin, lining of gut, white blood cells
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some cells do not regenerate
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muscle cells, nerve cells
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reasons for cell division:
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cell growth
repair and replace damaged cell parts reproduction of the species |
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instructions for making cells are found in
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the DNA
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each new cell must get a __ set of DNA
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complete
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DNA must be __ before cell division
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copied
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DNA
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deoxyribose nucleic acid
is a long thin molecule that stores genetic information |
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human DNA consists of about
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6 billion pairs of nucleotides
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DNA is organized into giant molecules called
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chromosomes
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chromosomes are made of
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protein and long single tighty coled DNA molecules visible only when the cell divides
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when a cell is not dividing DNA is
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less visible and called chromatid
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DNA in eukaryotes wraps tightly around proteins called__ to help pack the DNA during cell division
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histones
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non histone proteins help
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control the activity of specific DNA genes
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Kinetochore proteins bind to __ and attach chromosomes to the __ in mitosis
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centromere; spindle
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centromeres hold
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duplicated chromosomes together vefore they are separated in mitosis
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Telomeres
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are at the end of chromosomes which are important in
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each half of the chromosome is called __ when DNA makes compies of itself before cell division
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sister chromatid
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plasmid
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one circular chromosoe attached tot he inside of the cell membrane; DNA in a prokaryote
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humans have __ chromosomes and __ pairs
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46; 23
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homologues
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2 chromatids of a chromosome pair; have genes for same trait at same location
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human reproductive cells have one set of __ chromosomes (haploid or n number)
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23
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fertilization restores the __ chromosome numbers in the egg
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diploid
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sex chromosomes, either X or Y, determine the __ of the organism
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sex
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two X chromosomes
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will be a female
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XY chromosomes will be
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a male
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autosomes
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all other chromosomes besides sex chromosomes
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karytype
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chromosomes from a cell arranged in pairs by size starting witht he longest pair and ending with the sex chromosomes
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a human karyotype has
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22 pairs of autosomes and 1 pair of sex chromosomes (23) total
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gene
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is a section of DNA which codes for a protein
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each gene codes for
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one protein
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humans have about __ genes or __ per chromosome
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100,000; 2000
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about __ of the DNA is chromosome is "junk" that does not __
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95; code for any proteins
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cells go through phases or a __ during their life before they divide to form new cells
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cell cycle
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The cell cycle include
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interphase and cell division
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cell division includes
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mitosis, and cytokinesis
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mitosis
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nuclear division
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cytokinesis
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division of the cytoplasm
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interphase is the __ and is called __
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the longest part of a cells life cycle; resting stage because the cell isnt dividing
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interphase consists of 3 parts:
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G1 S1 G2
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G1
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1st growth phase, occurs after the cell has undergone cell division; cell matures, increases in size, more cytoplasm, makes organelles
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S
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synthesis phase follows G1, genetic material is replicated
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G2
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2nd growth phase occurs after S phase, cell maeks all the structure needed to divide.
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binary fission
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the way prokaryotes divide into two new identical cells, the chromosomes attatched to the cell membrane make copies of itself and the cell doubles in size. a wall then build in the middle of the two copied chromosomes and the parent cell forms two new identical cells
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binary fission is an __ method of reproduction
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asexual
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mitosis consist of 4 stages:
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prophase, metaphase, anaphase, telophase
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