Biology Semester 2 Exam Review Day 1

Natural Selection can best be described as the _____.

• survival of the biggest and strongest organisms in a population

• elimination of the smallest organisms by the biggest organisms

• survival and reproduction of the organisms that occupy the largest area

• survival and reproduction of the organisms that are genetically best adapted to the environment

Which statement best summarizes natural selection?

• Fit organisms survive, reproduce, and pass on their traits to offspring.

• Fit organisms are stronger and enable the less fit organisms to adapt.

• 1. All organisms survive, acquire traits, and pass those traits to offspring.

• All organisms adapt to the limited resources, which makes them successful.

A population of birds had a range of beak sizes.  These birds ate different sizes of seeds.  After a prolonged drought, only the larger, tougher seeds were available.  Only birds with larger beaks could eat these seeds.  As a result, the population changed so that there were no longer birds with the smaller beaks.  Which of the following best describes what happened to this population?

• Natural selection led to a reduction in biodiversity.

• 1. Environmental conditions led to speciation.

• Genetic drift led to increased adaption

• Selection pressures led to gene flow.

Sunflower Plants

-A population of sunflower plants has seeds with three different types of seed coats or shells.

-The three seed coat phenotypes that exist are thick, thin, and brittle.

-A change in the climate of the plants’ environment favors the hard-seed coats.

Which of the following describes what will MOST LIKELY happen to the plants as a result of this change in climate?

• All of the individual plants will change their DNA to produce hard-seed coats.

• Some of the individual plants will change their DNA, the rest will not survive

• Over time, more plants will produce seeds with hard coats.

• The thin-seed plants will begin to develop hard seed coats, but the brittle-seed plants will not change.

What are some risk factors for developing heart disease?

• poor diet

  
  

• smoking

• family history

• all of these are risk factors

Which type of cholesterol is considered to be the “good” cholesterol

• LDL

• HDL

• Both

• Neither

Why is LDL cholesterol considered to be the "good" choleserol?

• 1. it carries the cholesterol to our cell

• it helps build muscles

• absorbs and removes excess cholesterol out of the blood and into the liver

Why is too much cholesterol not healthy?

• 1. It blocks the arteries so blood cannot flow freely

• 1. It builds up the cell membranes

• 1. It leaks out of our skin and causes body odor

• cholesterol is super healthy so we should eat LOTS of it!

Match the correct statement with this image.

• Protein A separates into its own membrane compartment and the LDL particle is broken into tiny parts by the lysosome and its enzymes. Those cholesterol parts are free in the cell.

• LDL particles move through the bloodstream coming into contact with our cells.

  
  

• Protein B is in and outside the cell. It binds to the protein A and LDL pair and moves into the cell in a membrane compartment. All of the proteins and the LDL are broken down in that compartment where it stays.

  
  

•  Protein A and the membrane compartment go back to the cell membrane and start over to bind with LDL particles.

• LDL particles bind to protein A, which is then absorbed into the cell within a membrane compartment

  
  

True or False. High cholesterol is ONLY cause from eating unhealthy foods.

• TRUE

• FALSE