Biology Midterm 3 Part 4 Flashcards
Explain the Central Dogma of Molecular Biology
The central dogma of molecular biology states that genetic information flows in one direction only, from DNA to RNA to protein, meaning that the sequence of nucleotides in DNA is transcribed into RNA, which is then translated into the amino acid sequence of a protein; essentially, DNA provides the instructions for making proteins through an intermediary molecule called RNA
Define gene expression and describe how it relates to a cell’s function and phenotype
Gene expression is the process by which a cell converts the information in DNA into a functional product, like a protein. It’s a fundamental process that controls when and how much RNA and proteins are made, and it’s essential for a cell’s structure and function
Illustrate a signal transduction pathway and predict what would happen to the cell’s function if specific proteins were
mutated
A typical signal transduction pathway involves a ligand binding to a cell surface receptor, which then triggers a cascade of intracellular events, ultimately leading to a specific cellular response; if key proteins within this pathway are mutated, the cell might fail to respond to the signal properly, potentially causing abnormal cell behavior, like uncontrolled growth or impaired differentiation, which can be linked to diseases like cancer
Describe the types of mutations that must occur for a tissue to become cancerous
For a tissue to become cancerous, mutations typically need to occur in specific genes called “proto-oncogenes” which turn into “oncogenes” (causing uncontrolled cell growth) and “tumor suppressor genes” (which normally act as brakes on cell division), where mutations in these genes essentially remove the cell’s ability to regulate its own growth, leading to uncontrolled proliferation and cancer development; often, multiple mutations in different genes are required for a cell to become cancerous
Describe evidence that might be used to determine whether a species has historically reproduced sexually or asexually
To determine if a species historically reproduced sexually or asexually, scientists can examine evidence like: genetic diversity within a population (low diversity indicates a history of asexual reproduction), the presence or absence of sex-specific traits, the existence of mating behaviors, the analysis of reproductive genes, and fossil records showing morphological changes associated with sexual reproduction; all of which can provide clues about the dominant reproductive strategy of an ancestral population
Compare the advantages and disadvantages of sexual and asexual reproduction
Sexual reproduction offers the advantage of increased genetic diversity within a population, allowing for better adaptation to changing environments, while asexual reproduction is faster and more energy efficient, but lacks genetic variation, making populations more vulnerable to environmental changes; essentially, sexual reproduction provides adaptability while asexual reproduction prioritizes rapid population growth in stable environments
Distinguish between the following pairs of terms, including structure and function of each: sex chromosomes versus autosomes, somatic cells versus gametes, and diploid versus haploid cells
Somatic cells vs. Gametes:
Somatic cells are any body cell in an organism, responsible for the structure and function of the body, while gametes are reproductive cells (sperm and egg) that carry only half the genetic information needed to form a new individual, produced through meiosis.
Diploid vs. Haploid cells:
A diploid cell contains two complete sets of chromosomes (one from each parent), representing the typical chromosome number in most body cells, while a haploid cell contains only one set of chromosomes, found in gametes
Compare meiosis and mitosis and how meiosis relates to the inheritance of cancer
Meiosis is a specialized cell division process that creates gametes (sperm and egg cells) with half the genetic material of the parent cell, while mitosis is a process that produces two identical daughter cells with the same genetic material as the parent cell; the key connection to cancer lies in the fact that abnormal meiotic processes can lead to genetic instability, which is a major factor in cancer development, as it can result in mutations being passed on to offspring that could predispose them to cancer
Identify and summarize the ways sexual reproduction leads to genetic variation
Sexual reproduction leads to genetic variation primarily through the processes of crossing over (genetic recombination) during meiosis, independent assortment of chromosomes, and random fertilization where gametes from different parents combine, resulting in offspring with unique combinations of alleles from both parents, creating diversity within a population
Compare the functions, cellular processes, and cellular products of asexual and sexual reproduction
Asexual reproduction involves a single parent producing genetically identical offspring through mitosis, while sexual reproduction involves two parents contributing genetic material to create unique offspring via meiosis and fertilization; in essence, asexual reproduction produces clones, while sexual reproduction generates genetic diversity.
