Ch 4 Flashcards
DNA and other nucleic acids are
polymers of nucleotides
* Each DNA nucleotide consits of what three things?
- Sugar (deoyribose)
- Phosphate (Backbone)
- Nitrogenous base
* Which has Uracil, DNA or RNA?
RNA
* What are the hydrogen bonds DNA (nitrogenous) bases?
A ⇉ T
Adenine has a double hydrogen bond to Thymine
C ⇶ G
Cytosine has a triple bond to Guanine
What are the two purines?
- Adenine
- Guanine
What are the to pyrimidines?
- Cytosine
- Thymine
Genes are…
genetic instructions for the synthesis of proteins
A gene is…
a segment of DNA that codes for the production of a molecule of RNA that synthesizes a specific protein
The Genome are…
all the genes of one person.
* What types of cells do glands contain?
Cuboidal
Transcription occurs in the
nucleus
DNA ⟶ mRNA is the process of
Transcription
mRNA ⟶ Protein is the process of
Translation
mRNA =
messenger
rRNA =
ribosomal
tRNA =
Transfer
Translation is
the process that converts nucleotides into amino acids.
Ribosomes are resoponsible for
translating/converting the nucleotides (RNA) into amino acids (proteins)
Outline the process of translation/transcription to completed protein.
- DNA is duplicated in nucleus
- mRNA is released to ribosomes in the rough ER
- Ribosomes convert the mRNA info to proteins and releases to Golgi complex
- Golgi complex identifies the protein and packages it to be used inside the cell or to be released for extracellular use.
Before a cell divides, it must
duplicate its DNA
DNA controls all
cellular function
Give a general definition of the cell cycle.
The cell’s life cycle that extends from one cell division to the next.
What are the two main phases of the cell cycle?
- Interphase
- Mitotic Phase/M phase
* The cell spends most of its time in what phase?
Interphase
* What are the subphases of interphase?
- G0 (G zero)
- G1
- S
- G2
Explain G zero phase
The are cells that have left the cell cycle for a “rest” (ex. muscle and nerve cells)
Explain G1 phase
- first gap phase
- interal between cell division and DNA replication
- Accumulates materials needed to replciate DNA
* Explain S phase
- synthesis phase
- Duplicates centrioles
- DNA replication occurs
Explain the G2 phase
- second gap phase
- interval between DNA replication and cell division
- Finishes centriole duplication
- Synthesizes enzymes that control cell division
- Repairs DNA replication errors
Explain M phase
- Mitotic phase
- cell divides into two daughter cells
True or False
Cell cycle duration is the same between all cell types
FALSE
It varies between cell types
True or False
Cell division in all occurs in all body cells
FALSE
eggs and sperm do not go through mitosis
* What are the four phases of Mitosis?
P.M.A.T
- Prophase
- Metaphase
- Anaphase
- Telophase
What occurs in Prophase?
- Chromosomes condense and nuclear envelope breaks down
- spindle fibers grow from centrioles
- centrioles migrate to opposite poles of cell
What occurs in Metaphase?
- Chromosomes form around the midline of cell in preparation for division
What occurs in Anaphase?
- Centromeres divide in two
- Spindle fibers pull sister chromatids to opposite poles of cell
- Each pole now has identical set of genes
What occurs in Telephase?
- Chromosomes gahter at each pole of cell
- Chromatin decondenses
- New nuclear envelope appears at each pole
- New nucleoli appear in each nucleus
- Mitotic spindle vanishes (separation completed)
* Cells divide when…
- They have enough cytoplasm for two daughter cells
- They have replicated their DNA
- They have an adequate supply of nutrients
- They are stimulated by growth factor
- When neighboring cells die, opening up space in a tissue to be occupied by new cells
Cells stop dividing when…
- They snugly contact neighboring cells
- Nutrients or growth factors are withdrawn
- They undergo contact inhibition - the cessation of cell division in response to contact with other cells
Heredity is
the transmission of genetic characteristics from parent to offspring
Karyotype refers to
a chart of 46 chromosomes laid out in order by size and other physical features
The two members of eaich chromosome pair are called
homologous chromosomes
The SRY gene is responsible for developing
testosterone
Diploid cells are
any cell with 23 pairs of chromosomes
Diploid cells are also known as
Somatic cells
Haploid cells contain
half as many chromosomes as somatic cells
2 examples of haploid cells are
sperm and egg cells
What happens to haploid cells upon fertilization?
restores diploid number to the egg and they become somatic cells.
* Define Locus
the location of a particular gene on a chromosome
What is an Alleles?
Different forms of a gene at same locus on two homologous chromosomes
What are the two types of alleles?
- Dominant
- Recessive
What are the characteristics of a dominant allele?
- Corresponding trait is usually detectable in the individual
- Masks the effect of any recessive allele that may be present
- Produces protein responsible for visible trait
What are the characteristics of a recessive allele?
- Expressed only when present on both of the homologous chromosomes
- No dominant alleles at that locus
* Genotype are…
the genes you have.
* Phenotype is…
the physical expression of a gene (observable trait)
Homozygous alleles are
two identical alleles for a trait/gene
Heterozygous alleles are…
two different alleles for a trait/gene
* A gene pool is…
the collective genetic makeup of a population as a whole
Codominant alleles are…
both phenotypically expressed
Incomplete dominance results in…
a brand new (novel) phenotyipical manifestation
* Two sex-linked traits are
- color blindness
- hemophelia
What are the characteristics of a benign tumor?
- slow growth
- contained in fibrous capsule
- will not metastisize
- usually easy to treat
What are the characteristics of a malignant tumor?
- called cancer
- fast growing
- will metastasize
What does metastasize mean?
A cancer that gives off cells that seed the growth of multiple tumors elsewhere.
Oncology is
a medical specialty that deals with both benign and malignant tumors
Carcinoma is cancer of
the epithelial tissue
Lymphoma is cancer of
lymph nodes
Melanoma is cancer of
the pgiment cells of epidermis
Leukemia is cancer of
blood forming tissues
Sarcoma is cancer of
bone, connective tissue or muscle
A carcinogen is…
an environmental cancer-causing agent
Give three carcinogens with examples of each.
- Radiation: ultraviolet rays, x-rays
- Chemical: cigarette tar, food preservatives, industrial chemicals
- Viruses: HPV, hepatitis C, type 2 herpes simplex
What percentage of cancers are hereditary?
5-10%
Carcinogens trigger…
gene mutations
Oncogenes cause cell division to…
accelerate out of control
What do tumor-suppressor genes do?
inhibit development of cancer
ID: A
Extracellular Fluid
ID: B
Peripheral Protein
ID: C
Glycolipid
ID: D
Glycoprotein
ID: E
Carbohydrate chain
ID: F
Phospholipid bilayer
ID: G
Channel
ID: H
Peripheral protein
ID: I
Cholesterol
ID: J
Transmembrane protein
ID: K
Intracellular fluid
ID: L
Proteins of cytoskeleton
ID Cell Type: A
Receptor
ID Cell Type: B
Enzyme
ID Cell Type: C
Channel
ID Cell Type: D
Gated
ID Cell Type: E
Cell-identity marker
ID Cell Type: F
Explain the difference between
Genotype vs. Phenotype
- Genotype = Genes possessed
- Phenotype = Genes expressed
* Osteocytes are
mature bone cells
* Osteoblasts are
immature bone cells
* A cell spends most of its time ( of the cell cycle ) in
interphase
* Why is mitosis important for the growth and repair of tissue?
Mitosis will create new cells to replace cells lost in damaged tissue as well as fill in the gaps as tissue grows.
