Cells Flashcards
(27 cards)
Define gene
A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins.
Define the term chromosome
A chromosome is packaged and organized chromatin, a complex of macromolecules found in cells, consisting of DNA, protein and RNA.
Define nucleotide
a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.
What are the structure and parts of a DNA nucleotide
Double helix
Sugar phosphate backbone
A amd t
G and c
What is the difference between a triplet and a codon.
Triplet is DNA
Codon is RNA
the triplet sequence in the messenger RNA (mRNA) transcript which specifies a corresponding amino acid (or a start or stop command).
What is the process of mitosis
Interphase -normal stage of cell
Prophase -DNA replicate and condenses into chromosomes
Metaphase -every chromosome lines up down the middle
Anaphase -centroph pull chromosomes apart
Telophase - chromosomes group in opposite poles
Cytokesis- cells split in 2 cells
What is the process of meiosis
Prophase Metaphase Anaphase Telophase Prophase 2 Metaphase 2 Anaphase 2 Telophase w
What is the difference between mitosis and meiosis
Mitosis-
A process of asexual reproduction in which the cell divides in two producing a replica, with an equal number of chromosomes in each resulting diploid cell.
Meiosis-
A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes, producing two haploid cells.
Define allele
An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome.
What is homologous
pairing at meiosis and having the same structural features and pattern of genes.
Define heterozygous
If an individual has two different alleles at a specific locus, the individual is heterozygous at that locus; i
Example
Ss
hH
Define homozygous
Zygosity is the degree of similarity of the alleles for a trait in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid.
Define karyotype
the number and visual appearance of the chromosomes in the cell nuclei of an organism or species.
Define diploid and haploid
Having the same number of sets of chromosomes as a germ cell, or half the diploid number of a somatic cell. The haploid number (23 in humans) is the normal chromosome complement of germ cells. n. Having a single set of each chromosome in a cell or cell nucleus.
Where is RNA made
Inside the nucleus
Where does RNA go after the nucleus
then mRNA is transported out of the nucleus into the cytosol, where it is translated to protein by ribosomes.
What is the process of transcription
Process by which genetic information in the DNA is transferred to RNA. DNA sequence is enzymatically copied by the RNA to produce a complementary nucleotide RNA.
How many nucleotides in the mRNA code for one amino acid
Three
- codon
What is the process of translation
Initiation: amino acid attaches and starts to scan for a start signal.
Elongation: A new tRNA+amino acid enters the ribosome, If its anticodon matches the mRNA codon it basepairs and the ribosome can link the two aminoacids together.The ribosome then moves one triplet forward and a new tRNA+amino acid can enter the ribosome and the procedure is repeated.
Termination: When the ribosome reaches one of three stop codons, for example UGA, there are no corresponding tRNAs to that sequence. Instead termination proteins bind to the ribosome and stimulate the release of the polypeptide chain (.
When the genetic code Carried by messenger RNA directs the production of proteins from amino acids
What is a somatic cell…in relation to diploid
any cell of a living organism other than the reproductive cells
Like all cells, somatic cells contain DNA arranged in chromosomes. If a somatic cell contains chromosomes arranged in pairs, it is called diploid and the organism is called a diploid organism.
What is a sex cell
A haploid cell is a cell that contains one complete set of chromosomes. Gametes are haploid cells that are produced by meiosis
reproductive cell: a spermatozoon or an ovum; a cell responsible for transmitting DNA to the next generation
Difference between haploid and diploid
Diploid just means that the cell contains two sets of DNA (“di” means two). Most cells in the body are diploid. The diploid number of chromosomes in a human somatic (body) cell is 46.
Haploid means that the cell contains one set of DNA, half of a diploid cell. The haploid number of chromosomes in a human body cell is 23. A human haploid body cell denotes a sex cell (i.e. sperm, egg).
Difference between recessive and dominant alleles
Dominant allele: A single copy of gene is enough to express its character. Usually denoted by capital letter
eg: Tall in pea plant (T) TT and Tt both are tall
Recessive allele: Two copies of the gene is necessary to express its character. Denoted by small letter
eg: Dwarf/short in pea plant
Only tt is short.
Difference between dominant and recessive inheritance, incomplete inheritance and co-dominant inheritance
Codominance - A form of inheritance in which both alleles are equally shown.
Incomplete dominance - A form of inheritance in which the heterozygous alleles are both expressed, resulting in a combined phenotype.
Recessive Inheritance
Both parents carry a normal gene (N), and a faulty, recessive, gene (n). The parents, although carriers, are unaffected by the faulty gene. Their offspring are affected, not affected, or carriers. This type of inheritance was first shown by Mendel.
Dominant Inheritance
One parent has a single, faulty dominant gene (D), which overpowers its normal counterpart (d), affecting that parent. When the affected parent mates with an unaffected and non-carrier mate (dd), the offspring are either affected or not affected, but they are not carriers.
