Week 3 Flashcards
In animal development, what is fertilization?
Fertilization in animals is a biological process that involves a sperm (male gamete) merging with an egg (female gamete or ovum) to create a zygote, and leading to the development of an embryo.
What are gametes?
Gametes: A gamete is a reproductive cell of an animal or plant. In animals, female gametes are called ova or egg cells, and male gametes are called sperm. Ova and sperm are haploid cells, with each cell carrying only one copy of each chromosome.
What is the zygote?
a diploid cell resulting from two haploid gametes.
What occurs during cleavage? How is cleavage different in mammals compared to all other animals?
Cleavages are early cell divisions after fertilization partition the egg into a mass of undifferentiated cells. Cleavage is when the cytoplasm is split into smaller pieces.
Mammals undergo rotational cleavage which is unique to them.
What happens when you randomly change the nucleotide sequence of an open reading frame?
A Mutation occurs, which changes the amino acid that is later produced. The change of which amino acid is produced may or may not ultimately affect the protein that is produced. The structure, function, or stability of the resulting protein can be affected.
Define totipotent, pluripotent, and multipotent stem cells and use each one in a sentence.
Totipotent stem cell: Stem cells that have the ability to become any specialized cell in the adult body.
Pluripotent stem cell: A type of stem cell that normally only exists during early embryonic development. They are able to form all three of the basic body layers (ectoderm, endoderm, mesoderm), and even germ cells.
Multipotent: Multipotent stem cells have the ability to differentiate into all cell types within one particular lineage.
Terminally differentiated: A terminally differentiated cell is one that is specialized and has lost its ability to reproduce. EX: Neurons, skeletal/heart myocytes, adipocytes
Determined: A cell that is capable of differentiating on its developmental pathway to become a specialized cell.
Differentiation: The process during which young, immature (unspecialized) cells take on individual characteristics and reach their mature (specialized) form and function.
What is a somite?
Somites are groups of partially determined cells (multi or pluripotent stem cells) whose descendants become the vertebrae, the ribs, as associated skeletal muscle, cartilage, and tendons for the associated segments.
What is RNA splicing?
RNA splicing is a process in molecular biology where a newly-made precursor
messenger RNA transcript is transformed into a mature messenger RNA. It works by removing all the introns and splicing back together exons.
What is the advantage of RNA splicing strategies that the eukaryotes evolved?
It assists in the evolution process by forming different combinations of exons and thereby making new and improved proteins.
Describe the difference between prokaryotic and eukaryotic mRNAs
In prokaryotes, such as bacteria, mRNA is often polycistronic, meaning it can code for multiple proteins. In contrast, eukaryotic mRNA is typically monocistronic, encoding only one protein. Additionally, prokaryotic mRNA does not undergo post-transcriptional modifications, while eukaryotic mRNA undergoes processes such as capping, splicing, and polyadenylation to become mature and functional
What are transcription factors?
Transcription factors are proteins that regulate the transcription of genes. Transcription
factors bind to sequences in promoter regions. They either negatively or positively regulate the synthesis of mRNA.
Negative Regulation occurs when a repressor protein binds to the binding site on a promoter region and blocks transcription.
Positive Regulation occurs when an activator protein binds to the binding site on a promoter region and stimulates transcription.
What are sex cells?
An egg cell in females or sperm cell in males. Each mature sex cell contains 23 chromosomes (only half of the total genetic information).
What are germ cells?
A cell that develops into a reproductive cell, which is an egg in females and a sperm in males.
How are the three cell types related to each other?
They are all involved in sexual reproduction. Germ cells undergo meiosis and differentiate into mature gametes (eggs or sperm). Gametes and sex cells are the same thing.
What is organogenesis?
Organogenesis = development of organs from germ cell layers (p. 930). After 3 months, a human fetus has completed organogenesis.
