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Biology

The document outlines key concepts in cell biology, including the cell theory and the distinction between prokaryotic and eukaryotic cells. It details various organelles and their functions, such as the nucleus, mitochondria, and chloroplasts, as well as transport mechanisms like diffusion, osmosis, and active transport. Additionally, it explains the processes of mitosis and meiosis, highlighting their roles in cell division and genetic variation.

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lina
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12 views1 page

Biology

The document outlines key concepts in cell biology, including the cell theory and the distinction between prokaryotic and eukaryotic cells. It details various organelles and their functions, such as the nucleus, mitochondria, and chloroplasts, as well as transport mechanisms like diffusion, osmosis, and active transport. Additionally, it explains the processes of mitosis and meiosis, highlighting their roles in cell division and genetic variation.

Uploaded by

lina
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Biology – Cell Structure and Function

 Cell theory: all living things are made of cells; cells are the basic unit of life; all cells
come from pre-existing cells.
 Two main types of cells: prokaryotic (no nucleus, e.g., bacteria) and eukaryotic (nucleus,
organelles).
 Organelles:
o Nucleus: stores DNA, controls cell activities.
o Mitochondria: powerhouse, ATP production, site of cellular respiration.
o Ribosomes: protein synthesis, free vs. bound.
o Endoplasmic reticulum (ER): smooth ER – lipid synthesis, detoxification; rough
ER – protein synthesis.
o Golgi apparatus: modifies, sorts, and packages proteins.
o Lysosomes: contain digestive enzymes, break down macromolecules.
o Chloroplasts (in plant cells): photosynthesis, chlorophyll pigments.
 Cell membrane: semi-permeable, phospholipid bilayer, contains proteins and
carbohydrates for transport and signaling.
 Diffusion vs. osmosis: passive transport, movement from high to low concentration;
osmosis is specifically water movement.
 Active transport: requires ATP, moves molecules against concentration gradient.
 Mitosis: PMAT (prophase, metaphase, anaphase, telophase) – results in two identical
daughter cells.
 Meiosis: produces gametes, introduces genetic variation through crossing over.

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