Biology Test Two Flashcards
Cell cycle description
Process by which a cell reproduces itself.
Cell cycle phases
Interphase
Mitosis and cytokinesis
Cell cycle purpose
Producing sufficient ingredients such as organelles, cytoplasm, and DNA to make two new daughter cells.
Segregating a complete copy of those ingredients to each daughter cell to create two genetically identical cells.
Mitosis products
Two identical daughter cells
Mitosis sub divisions
Prophase
Metaphase
Anaphase
Telophase
Number of chromosomes
46
23 pairs
Why cell division is important
For normal growth, development, and repair of organisms.
Heals wounds
Cell checkpoints
G1-S
G2-M
M-A
Cell checkpoint jobs
Monitor each stage of cell cycle and check for mistakes such as DNA damage.
Prevent a cell from progressing to next stage until it accurately finishes current stage
Cell cycle checkpoint two mechanisms in regulating the cycle
If DNA damage is detected at checkpoint, a cell conducts DNA repair mechanism to repair damage.
If case is severe or irreversible damage, cp directs cell to commit suicide or apoptosis
Cancer cells caused by….
Specific proteins sometimes become damaged and can’t detect DNA damage. Cells can divide over and over again causing cancer.
Cancer is a disease of unregulated cell division. Inappropriate cell division and cells divide
Methods of fighting cancer
Chemotherapy- treatment that interferes with the cell cycle
Plant derived drugs- Interfere with chromosome separation during mitosis
Radiation therapy- beams of high energy electrons that kill dividing cells in specific area. Severely damages molecules and DNA.
Meiosis products
Gametes (sex cells)
4 genetically unique haploid gametes (daughter cells)
Purpose of meiosis
To halve the chromosome number from 46 to 23
Gametes
Sperm or egg are specialized reproductive cells that carry one copy of each chromosome. Haploid. Carry 23 chromosomes.
Order of events in Meiosis
When haploid sperm fertilizes a haploid egg, the result is a diploid zygote.
The zygote carries 2 copies of every chromosome and 2 copies of every gene on 46 chromosomes or 23 pairs.
Zygote will divide by mitosis to become an embryo
That will eventually grow into a human child.
Gene
Physically transmitted from parents to children.
Sequence of DNA that contains information to make up at least one protein.
Allele
Alternative version of the same gene that have different nucleotide sequences and are on homologous chromosomes.
Ex. Ff FF ff
Ff is gene and F is allele and f is allele.
Genotype
Genetic makeup of an organism
Ex. Blood AA, AO, BO…..
Phenotype
Visible traits or physical appearance of an individual
Ex. Curly hair
Dominant allele
An allele that can mask the trait of a recessive allele
Dark eyes
Curly hair
Freckles
Dimples
Recessive allele
Allele that reveals itself in the phenotype only of the organism has two copies of that allele.
Tongue rolling
Straight hair
Blue eyes
Location of X-Linked Traits
Located on X chromosome of mother or father
Who are carriers of X-Linked traits
Mom and dad
Who is affected by X-Linked Traits
Boys are affected more than girls, because if they get harmed X from mother, they definitely have disease, but girls get two X so they can be carrier only.
Duchenne Muscular Disease
X-linked disease Neuromuscular disease that is caused by a mutation on X-Chromosome Recessive disease gene Passed from mother to children Affects more boys than girls
Muscle slowly degenerates. Leads to paralysis
Most affected boys are in wheelchair by teenage years
Hemophilia
Blood clotting disease.
X-Linked trait
Color blindness
Some men cannot distinguish red from green
X-Linked trait
Y chromosome and it’s importance or use
Used to analyze and study ancestry, to fill in missing pieces of historical info and to identify paternity.
Transmitted unchanged from father to son.
Recessive Trait Diseases
Cystic fibrosis
Affects chromosome #7
CF alleles are defective
Symptoms: Mucus build up in lungs Trouble breathing Susceptible to bacterial infections Lung damage caused by repeated infection May cause death
Dominant trait disease
Huntingtons- mental retardation
Polydactyly- having more than five fingers or toes
Caused by inheriting one or two dominant alleles having defective genes
Aneuploidy
When chromosomes fail to separate accurately during cell division in meiosis
Resulting gametes carry an abnormal number of chromosomes
Egg or sperm cell has too many or too few chromosomes
Can cause death in fetus
Or Down syndrome
Trisomy 21
Down syndrome
Results when an embryo inherits extra copy of chromosome 21.
Karyotype
Diagram of all chromosomes in a cell or it represents the chromosomal make up of a cell in an Individual.
DNA function and importance
Hereditary molecule that is passed from parents to offspring.
Instructs for making proteins.
Serves as the instruction manual of how to build an individual.
“Blue print”
DNA double helix
made up of two strands of molecules.
Each strand consists of a chain of molecules called nucleotides that are bounded together.
Nucleotides
Building blocks of DNA. Adenine thymine Guanine Cytosine
DNA replication base pairing rule
Between DNA strands guides replication of two new strands.
1st original strands of double helix unzip
Then new strands zip to original ones
Two new molecules of DNA are formed. One original and one side new.
DNA profile
Visual representation of a persons unique DNA sequence.
Takes advantage of the fact that no two people have exact same DNA sequence except for twins.
Used in forensic science analysis. STR sequence.
STR
Short tandem repeats.
Sections of a chromosome in which DNA sequences are repeated.
Found in non coding regions of DNA.
Non coding regions
DNA sequences that do not hold instructions to make proteins. Strs are found here.
Act act act act act act act
Noncoding sequences are dif between ind.
Coding regions
Sequences of DNA that serve as instructions for making proteins.
Atcccggtctactg
Coding sequences are similar from person to person.
Protein
Macromolecule made up of repeating subunits known as amino acids.
Function of protein
Allow muscles to contract, give hair texture, facilitate thousands of chemical reactions in our cells.
Examples of proteins
Hemoglobin- carries oxygen in blood vessels.
Anti thrombin- prevents the blood clotting in vessels such as in heart and lungs.
Antibody molecules- part of body’s defenses
Protein shape
Come in many dif shapes and sizes depending on repeating amino acids.
Three dimensional figure
Amino acids
Building blocks of proteins.
Determine shape and function of produced protein.
20 dif.
Shape of protein determines it’s function.
Transcription
Occurs in nucleus of eukaryotic cells.
First step in gene expression
Copies coding sequence of DNA into complementary mRNA
DNA- mRNA
mRNA copy from DNA, leaves nucleus and enters cytoplasm to enter ribosome for translation and production of protein
Translation
Occurs in ribosomes.
Second stage of gene expression.
On ribosome in cytoplasm, translation reads mRNA sequence to assemble corresponding amino acid sequence with help of tRNA to make protein.
mRNA- tRNA- protein.
Ribosome moves along mRNA and reads it in groups of three nucleotides which are called codons.
Complete path of gene expression
DNA
mRNA
tRNA
Protein
Codon
Sequence of three mRNA nucleotides that specifies a particular amino acid
Anticodon
Part of the mRNA molecule that binds to a complementary mRNA codon
mRNA
RNA copy of an original DNA sequence made during transcription
tRNA
Type of RNA that helps ribosomes assemble chains of amino acids during translation
Transgenic organism
GMO
Carryover me or more genes from a different species.
Have been genetically modified by humans.
Steps of production of anti thrombin using GMOs
- Goats regulatory sequence and humans anti thrombin coding sequence are joined together.
- Micro injection and embryo transfer process in which the prepared gene is injected into fertilized goat embryo. These embryos are implanted into a surrogate goat mother who give birth to transgenic offspring.
- Anti thrombin protein is expressed in milk in females. Can be isolated and from milk and used as medicine to treat antithrombin deficient people.
