It is best to tackle each chapter at least 3 times. The first time you should skim the chapter, noting topic sentences, words in bold print, all tables, diagrams and summary charts. This is best read before the lecture. The second reading should be in more detail, studying each area and not proceeding until each section is understood. Reread each section as of many times as necessary until you understand its meaning.
Mastery can take minutes or hours or days.
Talk to yourself as you read. Explain what you have read aloud and make up your own examples to better understand what you have read. Rereading the material aloud, especially in your own words helps clarify the information. Hearing yourself makes a lot of difference. Words and symbols of biology have specific meanings.