Chapter 3 Flashcards
What are the fundamental units of life in all organisms?
cells
what type of cells on earth began life?
sukaroyotic cells
these cells are three dimensional structures composed of carbohydrates, lipids, nucleic acid, proteins, and substructures called organelles
sukaroyotic cells
What is a nucleus?
a part of cell surrounded by cytoplasm, (which breaks down nutrients and converts them to other substances to store energy through protein synthesis), a nucleus contains DNA and RNA
What do mitochondria do?
produce energy within a cell
What do ribosomes do?
assist in protein synthesis
what are somatic cells?
they are cells composed of body cells
what are gametes?
reproductive cells
What are the three most important aspects of DNA code?
The code is triplet, the code is continuous ,the code is redundant, the code is universal
What did Crick and watson do?
find DNA in 1953
DNA is composed of what?
two chains of small units called nucleotides- these are made up of a sugar molecule, a phosphate group, and one nitrogenous base.
What are the four bases of the double helix in DNA?
adenine, guanine, thymine, and cytosine- this allows for DNA to replicate
DNA replication happens when?
When a cell divides and enzymes break the bond between bases through DNA, attraction occurs in a complimentary way (A’s only to T’s etc)
What is the assembly of protein in a cell called?
protein synthesis
Where does protein synthesis take place?
outside the cell nucleus,
What do enzymes do?
regulate chemical reactions
What is RNA also called?
messenger DNA
What are the 3 important aspects of RNA?
- Single Stranded, 2. contains a different type of sugar 3. contains the base uracil as a substitute for the DNA base thymine
What are mRNA triplets called?
condons
What does mRNA do?
transfers RNA (tRNA) to the ribosome
What do ribosomes do?
join everything within the cell together
What is a gene?
a sequence of DNA bases that specifies the order of amino acids in an entire protein, a portion, or any functional product (i.e. RNA). A gene made be made up of hundreds or thousands of DNA bases organized into coding and non-coding segments.
Genome
the entire genetic makeup of an individual or species
how many DNA bases do humans have?
3 billion
Exons
segments of genes that are transcribed and are involved in protein synthesis
Introns
segments of genes that are initially transcribed and then deleted. Are not involved in protein synthesis
Regulatory Genes
Genes that influence the activity of other genes
Why are regulatory genes important to evolution?
direct embryonic development and are involved in many processes throughout life
homeobox genes
an evoutionarily ancient family of regulatory genes that direct the development of the overall body plan and segmentation of body tissues
what are responsible for various physiological differences between closely related species or different breeds of domesticated animals?
homeobox genes
What does sickle-cell anemia result from?
a defective beta chain
What is a point mutation?
a change in one of the 4 DNA bases
Chromosomes
consist of DNA and protein, humans have 46, chimps have 48
Two types of chromosomes:
autosomes- all chromosomes except sex-chromosomes, and sex chromosomes or gametes
Locus
the position or location on a chromosome where a given gene occurs
alternate forms of a gene, occur at the same locus on paired chromosomes and thus govern the same trait
alleles
karyotype
the chromosome of an individual or what is typical of a species, viewed microscopically and displayed in a photograph
Mitosis
simple cell division, the process by which somatic cells divide to produce two identical daughter cells
Meiosis
cell division on specialized cells in ovaries and testes, involves two division and results in four daughter cells, these can develop into gametes
the exchange of genetic material between paired chromosomes during meiosis “crossing over”
Recombination
a problem occuring during meiosis where chromosomes in fetal development do not separate
nondisjunction
Clones
organisms that are genetically identical to another organism
the chance distribution of chromosomes to daughter cells during meiosis. An important source of genetic variation
random assortment
PCR
polymerase chain reaction-a method of producing thousands of copies of DNA samples for testing, allows for DNA fingerprinting
