First find the total number of claws the cat has: 4 claws/foot * 4 feet = <<4*4=16>>16 claws
Then find the total time Nissa spends cutting the claws: 16 claws * 10 seconds/claw = <<16*10=160>>160 seconds
Then find the total time she spends cleaning the cats' ears: 90 seconds/ear * 2 ears = 180 seconds
Then find how long the shampooing takes in seconds: 5 minutes * 60 seconds/minute = <<5*60=300>>300 seconds
Then add the time she spends on each task to find the total time she spends grooming the cat: 160 seconds + 180 seconds + 300 seconds = <<160+180+300=640>>640 seconds
#### 640