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33 Cards in this Set
- Front
- Back
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another name for meiosis
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reduction division
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union of sperm and egg =
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zygote cell
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definition of mitosis
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division of the nucleus where genetic information is passed to daughter cells
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what is meiosis for
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the continuance of species rather than individuals
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purpose of cell replication in multicellular organism
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growthdevelopmentmaintenancerepair
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purpose of cell replicating for unicellular
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reproduce only
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what does low nucleus:cytoplasm mean
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to much cytoplasm for nucleus to control effectively
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definition of differentiation
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the process of change from unspecialised to specialized cell
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what is specialization (differentiation) controlled by
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genes
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permanent cells
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nerve, muscle, retinal and lense of eye
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definition of stem cells
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embryonic cells that dont differentiate fully
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what are stem cells used for
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develop/repair add they can replace and differentiate into distinct types
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2 types of stem cells
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adultembryonic
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where is embryonic stem cell obtained from
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embryo
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where is adult stem cell
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exist is most matured tissue and supply with the specific replacement
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what is programmed cell death called?
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apoptosis and is removed by Phagocytic cells that engulf
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why is cell death important
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for defence mechanismit detects danger, apoptosis and releases chemical signal for surrounding cells to do so aswell
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bad way for cell death
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damaged cell bursts, releasing contents and causing inflammation to surrounding cells
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What is gene? |
Part of dna molecule that has instructions to make proteins |
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Chromosome structure |
Each body cell has 2 or each chromosome, forming matching pairs |
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How many chromosome do humans have |
46 chromo ( 22 pairs +2 sex chromo) |
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What do signals do |
Instructs to go from one step to another or not |
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3 phases or interphase |
G1, S, G2 |
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What 3 things happens during interphase |
Cells grow, replicate chromosome in nucleus and may specialise |
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What happens during metaphase |
Chromosomes move to central region of nucleus as nuclear membrane disappears |
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What are chromatids |
Double strands formed by chromosomes attached by centromere |
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What are spindles |
Network of fibres |
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What do spindles do in metaphase |
They draw centromere so chromosome align and disapear at anaphase |
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Binary fission ? |
Is cytokinesis in plants |
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What happens in prophase |
Chromosomes condense and are clearlyvisible as homologous pairs |
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At anaphase what happens |
Spindle fibre attach to centromere and pull chromatids apart |
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What happens at telophase |
Chromosomes move to opposite poles of cell |
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What happens at cytokinesis |
A membrane divides cell into two |
