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39 Cards in this Set
- Front
- Back
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Functions of the nucleus |
Control cellular structure Directs cellular activities Produces ribosomes |
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Nucleus contains |
Nucleoli Genes |
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Genes are arranged along? |
Chromosomes |
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Body cells are also known as? |
Somatic cells |
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How many pairs of chromosomes do body cells have? |
23 pairs |
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The two chromosomes making up a chromosome pair are called? |
Homologous chromosomes |
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Homologous chromosomes mean? |
Same colored bodies |
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One of each pair is from whom? |
From the father and one from the mother |
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Each chromosome consists of what? |
Segments of DNA |
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Alleles are? |
Alternative versions of a gene |
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Homozygous alleles have? |
Identical information for a trait |
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Heterozygous alleles have? |
Different information for a trait |
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What is cell division? |
The process by which cells reproduce themselves |
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What are the 2 types of cell division? |
Somatic cell division Reproductive cell division |
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What is somatic cell division? |
Aim is to replicate cells to replace dead or injured cells or add new cells during tissue growth Occurs through mitosis and cytokinesis |
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What is reproductive cell division? |
Aim is to produce the gamete cells (sperm & oocyte) required or the next generation Occurs through meiosis |
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Somatic cell division occurs through what 3 main stages? |
Interphase Mitosis Cytokinesis |
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What is interphase? |
Stage between actual cell division (metabolic or growth stage) Includes replication of DNA, duplication of organelles & cell growth |
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What is mitosis? |
Parent cell produces 2 identical cells that have the same number of chromosomes (23 pairs) as the parent cell There are four stages that involve the division of the nucleus |
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What is cytokinesis? |
Division of the cytoplasm |
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Cell processes of Interphase include: |
Metabolism Duplication Cell growth Production of more organelles in preparation for cell division |
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How does Interphase work? |
Doubling of genetic material DNA molecules unzip in the presence of enzymes Exposed bases pick up complementary bases and a mirror copy is formed along each old strand 2 complete and identical DNA molecules are formed |
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How does Mitosis work? |
Nuclear division: 4 stages in which the nucleus divides Cytokinesis: Division of the cytoplasm to create 2 new identical cells (daughter cells) Each new cell has 23 pairs of chromosomes (46) |
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What is Meiosis? |
Occurs in the gonads (testes and ovaries) Results in the production of haploid cells (n) that contain only 23 chromosomes Fertilization restores the diploid number of chromosomes (46) |
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Meiosis occurs in how many stages? |
Two stages Meiosis I Meiosis II |
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What is Meiosis I? |
Occurs following the interphase stage Has 4 stages Produces 2 cells that: are genetically different contain 23 chromosomes |
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2 Comparisons of mitosis and meiosis |
Mitosis: 2 daughter cells (2n=46) Genetically identical Meiosis: 4 daughter cells (n=23) Genetically variable |
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Meiosis in males |
Occurs in testes The 4 daughter cells mature into 4 sperm cells |
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Meiosis in females |
Occurs in ovaries The 4 daughter cells mature into: 1 secondary oocyte 3 polar bodies (which are discarded) |
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How can you increase genetic variation |
Crossing over |
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What is sexual reproduction? |
Is a means of providing offspring that are genetically different from the parents |
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What is crossing over and where does it happen? |
The exchange of genes between homologous (paired) chromosomes |
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What is an abnormality of cell division? |
Cancer |
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What is cancer? |
The group of diseases that results from uncontrolled or abnormal cell proliferation |
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The result of uncontrolled cell division |
Results in an excess tissue called a tumor (or neoplasm) |
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Malignant tumors undergo what? |
Metastases (the spread of cancerous cells to other parts of the body) |
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Do benign tumors undergo metastases? |
No (they do not spread) |
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How are cancers named? |
After the type of tissue in which it develops |
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Name 4 types of cancer and where they are found |
Carcinoma- arises from epithelial tissue Melanoma- arises from melanocytes Lymphoma- arises from lymphatic tissue (most commonly from lymph nodes) Leukaemia- arises from WBC |
