Genetics Flashcards
Why is Gregor Mendel considered to be the founder (father) of modern genetics and how do his findings along with subsequent findings by other scientists influence livestock and poultry industry today?
Through his diligent work in crossing lines of garden peas he was able to identify mathematical rules governing genetic inheritance. This led to the findings of other scientists including James Watson and Francis Crick (and Maurice Wilkins and Rosalind Franklin: who determined the structure of DNA) and others to explain the process of inheritance. Because we have an understanding of the power of genetics, we have been able to make significant gains in domesticated livestock and poultry species.
What is a chromosome?
carries genetic code
What are gametes?
male and female productive cells (sperm and egg)
What is heredity?
how traits are passed down from parent to offspring
Where is DNA found?
the nuclei
What are nucleic acids made of?
nucleotides
What are the three parts of nucleotides?
- sugar (deoxyribose)
- phosphate
- nitrogenous base
What are the four bases in DNA?
- adenine
- thymine
- cytosine
- guanine
What bases of DNA pair up together?
- adenine and thymine
- cytosine and guanine
What does thymine turn into when looking at RNA?
uracil
How many strands does DNA have?
2
How are DNA bases connected together?
hydrogen bonds
How are proteins involved in the body?
They are involved in:
-support
-structure
-acting as enzymes that makes all minds of materials
-protecting the body
What is gene regulation?
genes can be turned on and off
What are the two main purposes of mitosis?
growth & repair
Does mitosis create gametes?
no, that is meiosis
What is the main function of mitosis?
process where somatic cells replicate, each parent cell divides into two identical daughter cells and each is carrying a FULL chromosome
What is interphase?
resting phase between successive meiotic cell divisons, duplicating cells during this time
What comes first? mitosis/meiosis or interphase
interphase
What is the mitosis stage of division called?
PMAT
What occurs during mitosis’ prophase
the chromosomes thicken and condense
What occurs during mitosis’ metaphase?
the chromosomes line up in the middle of the cell and the nucleus disassembles
What happens in mitosis’ anaphase?
the chromosomes move to opposite sides of the cell (the spindles are what cause them to move)
What happens in mitosis’ telophase?
the chromosomes end up on the complete opposite ends of the cell. a nuclei is formed on both sides and it surrounds the chromosomes
What is cytokinesis?
final separation of the two cells (occurs after telophase)
What does meiosis create?
sperm and egg cells (gametes)
How many chromosomes are in a sperm and an egg?
23 each
Why is meiosis called reduction division?
it reduces the number of chromosomes to half the normal number so that, when fusion of sperm and egg occurs, baby will have the correct number
What happens during interphase?
growth, DNA replication, and cell functions occur
What is a centromere?
part of the chromosome where sister chromatids are held together
What is a chromatid?
strands of replicated chromosome
Define haploid
presence of a single set of chromosomes in an organism’s cells
What is a diploid
sexually reproducing organisms are diploids (having two sets of chromosomes, one from each parent)
Define homologous
chromosomes are approximately the same size and contain the same type of genes in the same location
Define recombinant chromosomes
DNA recombination involves the exchange of genetic material either between multiple chromosomes or between different regions of the same chromosome
Define nondisjunction
the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei
What is a recap of heredity?
-you have your chromosomes
-you see genes in the chromosomes
-the genes consist of portions of DNA
-DNA is made up with nucleotides and it’s bases that makes the difference in coding for traits
What is the main function of meiosis?
meiosis creates daughter cells that carry one-half of the normal number of chromosomes so that during fertilization each parent has contributed a sample of one-half of their genetic material
Define allele
two alternate forms of a gene on a pair of homologous chromosomes
Define a dominant gene
gene that overpowers and prevents the expression of recessive allele when the two alleles are present in heterozygous individual
Define recessive gene
a gene that has it’s phenotype masked by it’s dominant allele when the two genes are present together in an individual
Define qualitative traits
a trait expressed categorically because of a sharp distinction between phenotypes (e.g., black and read). usually only one or few pairs of genes are involved in the expression of a qualitative trait
Define quantitative traits
a trait expressed on a continuous/numerical scale because of a gradual variation from one phenotype to another (e.g., weaning weight). usually manly gene pairs and environmental influences are involved in the expression of such traits
What happens in meiosis’ prophase I?
the chromosomes condense and thicken then they line up in a HOMOLOGOUS pair (same size with same gene). one is paternal and one is maternal
What happens in meiosis’ metaphase I?
the chromosomes line up in pairs in the middle
What does crossing over mean and when does it occur?
the transfer of genetic information between homologous pairs. this happens during prophase I for meiosis
What happens during during meiosis’ anaphase I?
the chromosomes are pulled away to opposite ends of the cell by spindle fibers
What happens during meiosis’ telophase I?
the nuclei reform around the divided sets of chromosomes (cells are haploid at this point)
Do females have XX or XY chromosomes?
XX
Do males have XX or XY chromosomes?
XY (the sperm is what decides whether the fetus will be female or male)
Define locus (loci)
position of allele on the chromosome
Define genotype
individual’s collection of genes
Define phenotype
observable trait based on a genotype at a single locus or based on the interaction
What is the central dogma?
framework that describes the flow of genetic information within a biological system
What is replication (copying)?
cells copy their DNA to make sure the genetic information is passed on accurately when cells divide
What is transcription (making a message)?
the cell makes a temporary copy of a specific DNA segment called mRNA. the mRNA carries the genetic instructions from the cell’s nucleus to the cytoplasm
What is translation (building proteins)?
takes place in the cytoplasm, the cell uses the mRNA’s instructions to build proteins. this involves assembling amino acids into a chain, forming functional proteins
What is the structure of DNA?
double helix
What is a gene?
fundamental physical and functional unit of heredity
What is the structure of RNA?
single stranded, thymine is now uracil
what is the purpose of RNA?
- copying instructions
- carrying information to ribosome
- building proteins
What is the structure and purpose of proteins?
… idk
What is the purpose of meiosis?
Creates gametes (egg and sperm cells)
What are the four phases of meiosis?
Prophase 1
Metaphase
Anaphase
Telophase
What happens in prophase 1?
once the chromosomes pair up they do something called crossing over
What is crossing over when talking about meiosis?
once the chromosomes pair up they transfer their genetic info to each other
